COM组件相关的武器化开发技术

COM简介

由于网上关于直接调用windows内建com组件的编程技术比较稀少(至少我找了几天没找到),该文会简要介绍如何通过已知clsid在自定可执行文件中调用windows com接口,实现部分武器化技术。

文旨在简单介绍调用windows本身com组件的相关编程技术,由于本人非职业开发,理解可能存在一定偏差,如发现有明显错误,请务必直接联系本人(防止误人子弟略略略略略)。

阅读本文的朋友很大概率经常使用诸如atexec、wmiexec之类的横向移动工具,该类技术其实质也是对dcom(分布式com)组件的调用。

com本身是一种开发理念,旨在跨应用和语言共享二进制代码,其理念类似dll,但dll仅能被C/C++理解或遵循C调用规范的语言使用,com通过指明二进制模块必须编译成约定的结构解决了这个问题,其实现方式与c++的类相似,所以通常使用c++来实现一个com组件。

就windows中实现来看,com组件本身仍旧是标准的pe结构(dll/exe),只不过其内部包含了coclass,以及在注册表中注册了相关键值,以便我们找到并使用它。

原理

通常windows内建com已经在注册表内存储着相关信息,而自定义com需要创建注册表入口点告诉windows com组件服务器在上面位置,这个过程称之为注册(Registration),我们可以在HKEY_CLASSES_ROOT\CLSID\{clsid}位置找到所有windows已注册的com组件。

注册后com通过GUID(globally unique identifier)唯一标识符来寻找并使用这个com组件,理论上每一个GUID(有时也称UUID)都是唯一的,GUID在标识不同的对象时会有不同的称呼,标识类对象时称之为CLSID(类标识符)、标识接口时被称为IID(接口标识符)。

在每一个注册的clsid表项中都包含一个名为InprocServer32的子项,该子项内存有映射到该com二进制文件的键值对,操作系统通过该键值对将com组件载入进程或另起进程。(进程内组件和进程外组件,二进制代码的表现形式为dll(内)和exe(外))。

我们可以通过以下powershell代码遍历所有com组件和它导出的方法。

New-PSDrive -PSProvider registry -Root HKEY_CLASSES_ROOT -Name HKCR
Get-ChildItem -Path HKCR:\CLSID -Name | Select -Skip 1 > clsids.txt
$Position = 1
$Filename = "win10-clsid-members.txt"
$inputFilename = "clsids.txt"
ForEach($CLSID in Get-Content $inputFilename) {
Write-Output "$($Position) - $($CLSID)"
Write-Output "------------------------" | Out-File $Filename -Append
Write-Output $($CLSID) | Out-File $Filename -Append
$handle = [activator]::CreateInstance([type]::GetTypeFromCLSID($CLSID))
$handle | Get-Member | Out-File $Filename -Append
$Position += 1
}

通过C++实现调用

通常对com组件的利用很多文章都直接使用powershell代码调用接口,代码如下:

$handle = [activator]::CreateInstance([type]::GetTypeFromCLSID("xxx"))
$handle.shellxec('cmd.exe /c')

在这里我会介绍一种通过c++调用的方法,在介绍之前,先看一个简单的powershell案例,Charles Hamilton发现prchauto.dll拥有一个ProcessChain的类,该类公开的start方法和commdline属性。

接下来我们通过部分工具将这个简单案例使用c艹实现,我们先使用oleview打开这个com组件的实现文件。

可以看到processchain类导出了一个名为iprocesschain的接口,我们使用这个工具将这个类导出为IDL文件,然后使用MIDL工具将这个IDL文件转换成我们需要的C++的头文件,这个文件会定义这个类和接口的使用方法。

使用MIDL,生成的processchain.h就是我们需要的。

部分代码:

EXTERN_C const IID IID_IProcessChain;
#if defined(__cplusplus) && !defined(CINTERFACE)
MIDL_INTERFACE("79ED9CB4-3A01-4ABA-AD3C-A985EE298B20")
IProcessChain : public IDispatch
{
public:
virtual /* [propget][id] */ HRESULT STDMETHODCALLTYPE get_ExecutablePath(
/* [retval][out] */ BSTR *ExecutablePath) = 0;
virtual /* [propput][id] */ HRESULT STDMETHODCALLTYPE put_ExecutablePath(
/* [in] */ BSTR ExecutablePath) = 0;
virtual /* [propget][id] */ HRESULT STDMETHODCALLTYPE get_CommandLine(
/* [retval][out] */ BSTR *CommandLine) = 0;
virtual /* [propput][id] */ HRESULT STDMETHODCALLTYPE put_CommandLine(
/* [in] */ BSTR CommandLine) = 0;
virtual /* [propget][id] */ HRESULT STDMETHODCALLTYPE get_NonBlocking(
/* [retval][out] */ VARIANT_BOOL *NonBlocking) = 0;
virtual /* [propput][id] */ HRESULT STDMETHODCALLTYPE put_NonBlocking(
/* [in] */ VARIANT_BOOL NonBlocking) = 0;
virtual /* [propget][id] */ HRESULT STDMETHODCALLTYPE get_TimeoutPeriod(
/* [retval][out] */ long *TimeoutPeriod) = 0;
virtual /* [propput][id] */ HRESULT STDMETHODCALLTYPE put_TimeoutPeriod(
/* [in] */ long TimeoutPeriod) = 0;
virtual /* [id] */ HRESULT STDMETHODCALLTYPE Start(
/* [out] */ VARIANT_BOOL *TimerFired) = 0;
virtual /* [id] */ HRESULT STDMETHODCALLTYPE CancelWait( void) = 0;
virtual /* [id] */ HRESULT STDMETHODCALLTYPE Terminate( void) = 0;
};

接下来就是简单的编程实现了,如果我们能找到一个支持提权且能执行命令的com组件,那我们就又获得了一个新的bypassuac的方法。

代码

先贴实现效果:

win10的计算机有点大.jpg

processchain.h

/* this ALWAYS GENERATED file contains the definitions for the interfaces */
/* File created by MIDL compiler version 8.01.0622 */
/* at Tue Jan 19 11:14:07 2038
*/
/* Compiler settings for .\prchauto.IDL:
Oicf, W1, Zp8, env=Win32 (32b run), target_arch=X86 8.01.0622
protocol : dce , ms_ext, c_ext, robust
error checks: allocation ref bounds_check enum stub_data
VC __declspec() decoration level:
__declspec(uuid()), __declspec(selectany), __declspec(novtable)
DECLSPEC_UUID(), MIDL_INTERFACE()
*/
/* @@MIDL_FILE_HEADING( ) *
#pragma warning( disable: 4049 ) /* more than 64k source lines */
/* verify that the <rpcndr.h> version is high enough to compile this file*/
#ifndef __REQUIRED_RPCNDR_H_VERSION__
#define __REQUIRED_RPCNDR_H_VERSION__ 475
#endif
#include "rpc.h"
#include "rpcndr.h"
#ifndef __RPCNDR_H_VERSION__
#error this stub requires an updated version of <rpcndr.h>
#endif /* __RPCNDR_H_VERSION__ */
#ifndef __processchain_h__
#define __processchain_h__
#if defined(_MSC_VER) && (_MSC_VER >= 1020)
#pragma once
#endif
/* Forward Declarations */
#ifndef ___IProcessChainEvents_FWD_DEFINED__
#define ___IProcessChainEvents_FWD_DEFINED__
typedef interface _IProcessChainEvents _IProcessChainEvents;
#endif /* ___IProcessChainEvents_FWD_DEFINED__ */
#ifndef __IProcessChain_FWD_DEFINED__
#define __IProcessChain_FWD_DEFINED__
typedef interface IProcessChain IProcessChain;
#endif /* __IProcessChain_FWD_DEFINED__ */
#ifndef __ProcessChain_FWD_DEFINED__
#define __ProcessChain_FWD_DEFINED__
#ifdef __cplusplus
typedef class ProcessChain ProcessChain;
#else
typedef struct ProcessChain ProcessChain;
#endif /* __cplusplus */
#endif /* __ProcessChain_FWD_DEFINED__ */
#ifdef __cplusplus
extern "C"{
#endif
#ifndef __ProcessChainLib_LIBRARY_DEFINED__
#define __ProcessChainLib_LIBRARY_DEFINED__
/* library ProcessChainLib */
/* [version][uuid] */
EXTERN_C const IID LIBID_ProcessChainLib;
#ifndef ___IProcessChainEvents_DISPINTERFACE_DEFINED__
#define ___IProcessChainEvents_DISPINTERFACE_DEFINED__
/* dispinterface _IProcessChainEvents */
/* [uuid] */
EXTERN_C const IID DIID__IProcessChainEvents;
#if defined(__cplusplus) && !defined(CINTERFACE)
MIDL_INTERFACE("85C4AF17-4C7A-4EF0-9BE7-39B06351AFA6")
_IProcessChainEvents : public IDispatch
{
};
#else /* C style interface */
typedef struct _IProcessChainEventsVtbl
{
BEGIN_INTERFACE
HRESULT ( STDMETHODCALLTYPE *QueryInterface )(
_IProcessChainEvents * This,
/* [in] */ REFIID riid,
/* [annotation][iid_is][out] */
_COM_Outptr_ void **ppvObject);
ULONG ( STDMETHODCALLTYPE *AddRef )(
_IProcessChainEvents * This);
ULONG ( STDMETHODCALLTYPE *Release )(
_IProcessChainEvents * This);
HRESULT ( STDMETHODCALLTYPE *GetTypeInfoCount )(
_IProcessChainEvents * This,
/* [out] */ UINT *pctinfo);
HRESULT ( STDMETHODCALLTYPE *GetTypeInfo )(
_IProcessChainEvents * This,
/* [in] */ UINT iTInfo,
/* [in] */ LCID lcid,
/* [out] */ ITypeInfo **ppTInfo);
HRESULT ( STDMETHODCALLTYPE *GetIDsOfNames )(
_IProcessChainEvents * This,
/* [in] */ REFIID riid,
/* [size_is][in] */ LPOLESTR *rgszNames,
/* [range][in] */ UINT cNames,
/* [in] */ LCID lcid,
/* [size_is][out] */ DISPID *rgDispId);
/* [local] */ HRESULT ( STDMETHODCALLTYPE *Invoke )(
_IProcessChainEvents * This,
/* [annotation][in] */
_In_ DISPID dispIdMember,
/* [annotation][in] */
_In_ REFIID riid,
/* [annotation][in] */
_In_ LCID lcid,
/* [annotation][in] */
_In_ WORD wFlags,
/* [annotation][out][in] */
_In_ DISPPARAMS *pDispParams,
/* [annotation][out] */
_Out_opt_ VARIANT *pVarResult,
/* [annotation][out] */
_Out_opt_ EXCEPINFO *pExcepInfo,
/* [annotation][out] */
_Out_opt_ UINT *puArgErr);
END_INTERFACE
} _IProcessChainEventsVtbl;
interface _IProcessChainEvents
{
CONST_VTBL struct _IProcessChainEventsVtbl *lpVtbl;
};
#ifdef COBJMACROS
#define _IProcessChainEvents_QueryInterface(This,riid,ppvObject) \
( (This)->lpVtbl -> QueryInterface(This,riid,ppvObject) )
#define _IProcessChainEvents_AddRef(This) \
( (This)->lpVtbl -> AddRef(This) )
#define _IProcessChainEvents_Release(This) \
( (This)->lpVtbl -> Release(This) )
#define _IProcessChainEvents_GetTypeInfoCount(This,pctinfo) \
( (This)->lpVtbl -> GetTypeInfoCount(This,pctinfo) )
#define _IProcessChainEvents_GetTypeInfo(This,iTInfo,lcid,ppTInfo) \
( (This)->lpVtbl -> GetTypeInfo(This,iTInfo,lcid,ppTInfo) )
#define _IProcessChainEvents_GetIDsOfNames(This,riid,rgszNames,cNames,lcid,rgDispId) \
( (This)->lpVtbl -> GetIDsOfNames(This,riid,rgszNames,cNames,lcid,rgDispId) )
#define _IProcessChainEvents_Invoke(This,dispIdMember,riid,lcid,wFlags,pDispParams,pVarResult,pExcepInfo,puArgErr) \
( (This)->lpVtbl -> Invoke(This,dispIdMember,riid,lcid,wFlags,pDispParams,pVarResult,pExcepInfo,puArgErr) )
#endif /* COBJMACROS */
#endif /* C style interface */
#endif /* ___IProcessChainEvents_DISPINTERFACE_DEFINED__ */
#ifndef __IProcessChain_INTERFACE_DEFINED__
#define __IProcessChain_INTERFACE_DEFINED__
/* interface IProcessChain */
/* [object][oleautomation][nonextensible][dual][uuid] */
EXTERN_C const IID IID_IProcessChain;
#if defined(__cplusplus) && !defined(CINTERFACE)
MIDL_INTERFACE("79ED9CB4-3A01-4ABA-AD3C-A985EE298B20")
IProcessChain : public IDispatch
{
public:
virtual /* [propget][id] */ HRESULT STDMETHODCALLTYPE get_ExecutablePath(
/* [retval][out] */ BSTR *ExecutablePath) = 0;
virtual /* [propput][id] */ HRESULT STDMETHODCALLTYPE put_ExecutablePath(
/* [in] */ BSTR ExecutablePath) = 0;
virtual /* [propget][id] */ HRESULT STDMETHODCALLTYPE get_CommandLine(
/* [retval][out] */ BSTR *CommandLine) = 0;
virtual /* [propput][id] */ HRESULT STDMETHODCALLTYPE put_CommandLine(
/* [in] */ BSTR CommandLine) = 0;
virtual /* [propget][id] */ HRESULT STDMETHODCALLTYPE get_NonBlocking(
/* [retval][out] */ VARIANT_BOOL *NonBlocking) = 0;
virtual /* [propput][id] */ HRESULT STDMETHODCALLTYPE put_NonBlocking(
/* [in] */ VARIANT_BOOL NonBlocking) = 0;
virtual /* [propget][id] */ HRESULT STDMETHODCALLTYPE get_TimeoutPeriod(
/* [retval][out] */ long *TimeoutPeriod) = 0;
virtual /* [propput][id] */ HRESULT STDMETHODCALLTYPE put_TimeoutPeriod(
/* [in] */ long TimeoutPeriod) = 0;
virtual /* [id] */ HRESULT STDMETHODCALLTYPE Start(
/* [out] */ VARIANT_BOOL *TimerFired) = 0;
virtual /* [id] */ HRESULT STDMETHODCALLTYPE CancelWait( void) = 0;
virtual /* [id] */ HRESULT STDMETHODCALLTYPE Terminate( void) = 0;
};
#else /* C style interface */
typedef struct IProcessChainVtbl
{
BEGIN_INTERFACE
HRESULT ( STDMETHODCALLTYPE *QueryInterface )(
IProcessChain * This,
/* [in] */ REFIID riid,
/* [annotation][iid_is][out] */
_COM_Outptr_ void **ppvObject);
ULONG ( STDMETHODCALLTYPE *AddRef )(
IProcessChain * This);
ULONG ( STDMETHODCALLTYPE *Release )(
IProcessChain * This);
HRESULT ( STDMETHODCALLTYPE *GetTypeInfoCount )(
IProcessChain * This,
/* [out] */ UINT *pctinfo);
HRESULT ( STDMETHODCALLTYPE *GetTypeInfo )(
IProcessChain * This,
/* [in] */ UINT iTInfo,
/* [in] */ LCID lcid,
/* [out] */ ITypeInfo **ppTInfo);
HRESULT ( STDMETHODCALLTYPE *GetIDsOfNames )(
IProcessChain * This,
/* [in] */ REFIID riid,
/* [size_is][in] */ LPOLESTR *rgszNames,
/* [range][in] */ UINT cNames,
/* [in] */ LCID lcid,
/* [size_is][out] */ DISPID *rgDispId);
/* [local] */ HRESULT ( STDMETHODCALLTYPE *Invoke )(
IProcessChain * This,
/* [annotation][in] */
_In_ DISPID dispIdMember,
/* [annotation][in] */
_In_ REFIID riid,
/* [annotation][in] */
_In_ LCID lcid,
/* [annotation][in] */
_In_ WORD wFlags,
/* [annotation][out][in] */
_In_ DISPPARAMS *pDispParams,
/* [annotation][out] */
_Out_opt_ VARIANT *pVarResult,
/* [annotation][out] */
_Out_opt_ EXCEPINFO *pExcepInfo,
/* [annotation][out] */
_Out_opt_ UINT *puArgErr);
/* [propget][id] */ HRESULT ( STDMETHODCALLTYPE *get_ExecutablePath )(
IProcessChain * This,
/* [retval][out] */ BSTR *ExecutablePath);
/* [propput][id] */ HRESULT ( STDMETHODCALLTYPE *put_ExecutablePath )(
IProcessChain * This,
/* [in] */ BSTR ExecutablePath);
/* [propget][id] */ HRESULT ( STDMETHODCALLTYPE *get_CommandLine )(
IProcessChain * This,
/* [retval][out] */ BSTR *CommandLine);
/* [propput][id] */ HRESULT ( STDMETHODCALLTYPE *put_CommandLine )(
IProcessChain * This,
/* [in] */ BSTR CommandLine);
/* [propget][id] */ HRESULT ( STDMETHODCALLTYPE *get_NonBlocking )(
IProcessChain * This,
/* [retval][out] */ VARIANT_BOOL *NonBlocking);
/* [propput][id] */ HRESULT ( STDMETHODCALLTYPE *put_NonBlocking )(
IProcessChain * This,
/* [in] */ VARIANT_BOOL NonBlocking);
/* [propget][id] */ HRESULT ( STDMETHODCALLTYPE *get_TimeoutPeriod )(
IProcessChain * This,
/* [retval][out] */ long *TimeoutPeriod);
/* [propput][id] */ HRESULT ( STDMETHODCALLTYPE *put_TimeoutPeriod )(
IProcessChain * This,
/* [in] */ long TimeoutPeriod);
/* [id] */ HRESULT ( STDMETHODCALLTYPE *Start )(
IProcessChain * This,
/* [out] */ VARIANT_BOOL *TimerFired);
/* [id] */ HRESULT ( STDMETHODCALLTYPE *CancelWait )(
IProcessChain * This);
/* [id] */ HRESULT ( STDMETHODCALLTYPE *Terminate )(
IProcessChain * This);
END_INTERFACE
} IProcessChainVtbl;
interface IProcessChain
{
CONST_VTBL struct IProcessChainVtbl *lpVtbl;
};
#ifdef COBJMACROS
#define IProcessChain_QueryInterface(This,riid,ppvObject) \
( (This)->lpVtbl -> QueryInterface(This,riid,ppvObject) )
#define IProcessChain_AddRef(This) \
( (This)->lpVtbl -> AddRef(This) )
#define IProcessChain_Release(This) \
( (This)->lpVtbl -> Release(This) )
#define IProcessChain_GetTypeInfoCount(This,pctinfo) \
( (This)->lpVtbl -> GetTypeInfoCount(This,pctinfo) )
#define IProcessChain_GetTypeInfo(This,iTInfo,lcid,ppTInfo) \
( (This)->lpVtbl -> GetTypeInfo(This,iTInfo,lcid,ppTInfo) )
#define IProcessChain_GetIDsOfNames(This,riid,rgszNames,cNames,lcid,rgDispId) \
( (This)->lpVtbl -> GetIDsOfNames(This,riid,rgszNames,cNames,lcid,rgDispId) )
#define IProcessChain_Invoke(This,dispIdMember,riid,lcid,wFlags,pDispParams,pVarResult,pExcepInfo,puArgErr) \
( (This)->lpVtbl -> Invoke(This,dispIdMember,riid,lcid,wFlags,pDispParams,pVarResult,pExcepInfo,puArgErr) )
#define IProcessChain_get_ExecutablePath(This,ExecutablePath) \
( (This)->lpVtbl -> get_ExecutablePath(This,ExecutablePath) )
#define IProcessChain_put_ExecutablePath(This,ExecutablePath) \
( (This)->lpVtbl -> put_ExecutablePath(This,ExecutablePath) )
#define IProcessChain_get_CommandLine(This,CommandLine) \
( (This)->lpVtbl -> get_CommandLine(This,CommandLine) )
#define IProcessChain_put_CommandLine(This,CommandLine) \
( (This)->lpVtbl -> put_CommandLine(This,CommandLine) )
#define IProcessChain_get_NonBlocking(This,NonBlocking) \
( (This)->lpVtbl -> get_NonBlocking(This,NonBlocking) )
#define IProcessChain_put_NonBlocking(This,NonBlocking) \
( (This)->lpVtbl -> put_NonBlocking(This,NonBlocking) )
#define IProcessChain_get_TimeoutPeriod(This,TimeoutPeriod) \
( (This)->lpVtbl -> get_TimeoutPeriod(This,TimeoutPeriod) )
#define IProcessChain_put_TimeoutPeriod(This,TimeoutPeriod) \
( (This)->lpVtbl -> put_TimeoutPeriod(This,TimeoutPeriod) )
#define IProcessChain_Start(This,TimerFired) \
( (This)->lpVtbl -> Start(This,TimerFired) )
#define IProcessChain_CancelWait(This) \
( (This)->lpVtbl -> CancelWait(This) )
#define IProcessChain_Terminate(This) \
( (This)->lpVtbl -> Terminate(This) )
#endif /* COBJMACROS */
#endif /* C style interface */
#endif /* __IProcessChain_INTERFACE_DEFINED__ */
EXTERN_C const CLSID CLSID_ProcessChain;
#ifdef __cplusplus
class DECLSPEC_UUID("E430E93D-09A9-4DC5-80E3-CBB2FB9AF28E")
ProcessChain;
#endif
#endif /* __ProcessChainLib_LIBRARY_DEFINED__ */
/* Additional Prototypes for ALL interfaces */
/* end of Additional Prototypes */
#ifdef __cplusplus
}
#endif
#endif

main.cpp

#include <Windows.h>
#include "processchain.h"
#include <objbase.h>
#include <stdio.h>
#include <strsafe.h>
//定义com组件使用的bool值,其实质是一个二short类型。
typedef short VARIANT_BOOL;
#define VARIANT_TRUE ((VARIANT_BOOL)-1)
#define VARIANT_FALSE ((VARIANT_BOOL)0)
#define CLSID_ProcessChain L"{E430E93D-09A9-4DC5-80E3-CBB2FB9AF28E}"
#define IID_IProcessChain L"{79ED9CB4-3A01-4ABA-AD3C-A985EE298B20}"
int main(int argc, TCHAR* argv[])
{
HRESULT hr = 0;
CLSID clsidIProcessChain = { 0 };
IID iidIProcessChain = { 0 };
IProcessChain* ProcessChain = NULL;
BOOL bRet = FALSE;
CoInitialize(NULL);//初始化com环境
CLSIDFromString(CLSID_ProcessChain, &clsidIProcessChain);
IIDFromString(IID_IProcessChain, &iidIProcessChain);
//创建接口
hr = CoCreateInstance(clsidIProcessChain, NULL, CLSCTX_INPROC_SERVER, iidIProcessChain, (LPVOID*)&ProcessChain);
TCHAR cmd[] = L"C:\\WINDOWS\\system32\\calc.exe";
VARIANT_BOOL b= VARIANT_TRUE;
//设置参数
ProcessChain->put_CommandLine((BSTR)cmd);
//调用方法
hr = ProcessChain->Start(&b);
//释放
CoUninitialize();
return 0;
}

LINKS

https://dl.packetstormsecurity.net/papers/general/abusing-objects.pdf