https://github.com/JLospinoso/gargoyle

A memory scanning evasion technique
https://github.com/JLospinoso/gargoyle

assembly memory-analysis pic rop-gadgets security x86

Last synced: 21 days ago
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A memory scanning evasion technique

• Host: GitHub
• URL: https://github.com/JLospinoso/gargoyle
• Owner: JLospinoso
• License: agpl-3.0
• Created: 2017-03-04T02:16:52.000Z (almost 8 years ago)
• Default Branch: master
• Last Pushed: 2017-05-24T00:23:54.000Z (over 7 years ago)
• Last Synced: 2024-11-20T05:44:42.518Z (22 days ago)
• Topics: assembly, memory-analysis, pic, rop-gadgets, security, x86
• Language: C++
• Homepage: https://jlospinoso.github.io/security/assembly/c/cpp/developing/software/2017/03/04/gargoyle-memory-analysis-evasion.html
• Size: 979 KB
• Stars: 838
• Watchers: 28
• Forks: 113
• Open Issues: 1
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
![gargoyle title](https://github.com/JLospinoso/gargoyle/raw/master/title.png)

![gargoyle infographic](https://github.com/JLospinoso/gargoyle/raw/master/infographic.png)

# Building gargoyle

*gargoyle* is only implemented for 32-bit Windows (64-bit Windows on Windows is fine). You must have the following installed:

* [Visual Studio](https://www.visualstudio.com/downloads/): 2017 Community is tested, but it may work for other versions.

* [Netwide Assembler](http://www.nasm.us/pub/nasm/releasebuilds/?C=M;O=D) v2.12.02 x64 is tested, but it may work for other versions. Make sure `nasm.exe` is on your path.

Clone *gargoyle*:

```sh

git clone https://github.com/JLospinoso/gargoyle.git

```

Open `Gargoyle.sln`, build, and run. There is some harness code in `main.cpp` that configures the following three components:

* *gargoyle* stack trampoline, stack, and configuration (read/write memory on the heap)

* *gargoyle* position independent code (PIC) that receives the ROP gadget/stack trampoline and runs arbitrary code

* A ROP gadget. If you have `mshtml.dll`, *gargoyle* will load it into memory and use it. If it is not available, you will have to tell *gargoyle* to allocate its own (3-byte) ROP gadget on the heap:

```cpp

// main.cpp

auto use_mshtml{ true };

auto gadget_memory = get_gadget(use_mshtml, gadget_pic_path);

```

Every 15 seconds, gargoyle will pop up a message box. When you click ok, gargoyle sets up the tail calls to mark itself non-executable and to wait for the timer. For fun, use [Sysinternals's excellent VMMap tool](https://technet.microsoft.com/en-us/sysinternals/vmmap.aspx) to examine when *gargoyle*'s PIC is executable. If a message box is active, *gargoyle* will be executable. If it is not, *gargoyle* should not be executable. The PIC's address is printed to `stdout` just before the harness calls into the PIC.

# More information

See the blog post [available at lospi.net](https://jlospinoso.github.io/security/assembly/c/cpp/developing/software/2017/03/04/gargoyle-memory-analysis-evasion.html) for more information.

Also feel free to hop on gitter: [![Join the chat at https://gitter.im/grgyl/Lobby](https://badges.gitter.im/grgyl/Lobby.svg)](https://gitter.im/grgyl/Lobby?utm_source=badge&utm_medium=badge&utm_campaign=pr-badge&utm_content=badge)