日本語版：README_JA.md

This repository contains a simple Live2D model that crashes any application that attempts to load it: a denial of service attack. If you have the ImHex hex editor installed, you can inspect and edit the MOC3 file with the pattern file in src/moc3.hexpat. Please note you will need to change the 0x7FFFFFFF (FF FF FF 7F) runtime space offset value near the beginning of the file to something sane (0) to be able to see the pattern data. Alternatively you can enable ShowRuntimeSpaceFields from the Settings tab.

src/moc3.hexpat should be able to view all MOC3 files. If you find one that it can't view, please file an issue and we'll look into it.

The included files can also be used as a template for further research and experimentation.

These files are released in the hope that they will prompt Live2D to improve their security practices.

There is only one widespread MOC3 reader implementation: Live2D Cubism Core. Cubism Core is a C library that makes no attempts to perform bounds checking on offsets contained within MOC3 files. As a result, it is trivial to read and write memory out of the bounds of the MOC3 data in memory, and it is almost certainly possible to execute arbitrary code this way.

As of now, I have not found a way to achieve code execution using Cubism Core alone; however, code execution may still be possible by taking advantage of the host program's (e.g. Cubism Viewer, VTube Studio, etc.) memory layout.

Direct ZIP download for the MOC3ingbird model (this repository): click here.

If you have Live2D's Cubism Editor (and Viewer) or any other software that can load Live2D models, simply open the exploit.moc3 file with it.

For the viewer bundled with the Live2D Cubism Editor, you can download this repository, and drag exploit.moc3 into the viewer. It will begin to load the model, and instantly crash.

If you attach a debugger to the crashing application, you should see the EXCEPTION_ACCESS_VIOLATION exception, SIGSEGV, or some other equivalent. The current PoC writes a pointer to moc3BaseAddress + sections.parts.runtimeSpace0 with the value moc3BaseAddress + sections.parts.ids.

The src/moc3.hexpat pattern supports all MOC3 files. Some samples may be found at https://live2d.com/en/download/sample-data/. Please note those samples are copyrighted by Live2D Inc. and may come with extra restrictions. The OpenL2D Project Developers are not responsible for ensuring the compliance of users of this software with any third-party agreements.

Copyright © 2023 The OpenL2D Project Developers. All rights reserved.

This model and all related files are free software licensed under the terms of the Free Development Public License 1.0-US as published by the Freedom of Development Project at https://freedevproject.org/fdpl-1.0-us. Usage of the files in this repository constitutes acceptance of this license.

No file in this repository was derived from the output of any Live2D software. All rights reserved only to the OpenL2D Project Developers, who, regarding the distribution of these files, have no obligations to any party under any agreement.

To be more explicit: you are free to use the included model files and pattern files to create your own MOC3 readers and writers. No license will restrict your right to do so.