Hex-Rays is a powerful tool for reverse engineering executable files, but sometimes you may need to modify the code or fix some bugs. In this article, you will learn how to patch executable files with Hex-Rays and how to collaborate and share the patched files with others.
Patching executable files can have many benefits, such as improving the functionality, performance, or security of an application. For example, you may want to patch a file to remove malware, add features, or fix errors. Patching can also help you understand how the file works and how to exploit its vulnerabilities.
One example I have done personally is having to fix an off-by-one error when I didn't have access to the source code. In that case I had to disassemble the software, find the location of the wrong instruction, and modify that location in the software binary. A pretty simple fix that saved the time waiting for someone to modify the source code.
Hex-Rays is a decompiler that converts executable files into readable and editable C code. To patch a file with Hex-Rays, you need to open it in IDA Pro, a disassembler that analyzes the binary code and creates a database of the file structure. Then, run Hex-Rays to generate the C code, which can be viewed in a separate window or in a split view with the assembly code. To locate the function or variable you want to patch, use the search function or the cross-references to find the relevant code. After making your edits, save the changes and apply the patch to the file by selecting the patch option from the menu or pressing Ctrl+P. Hex-Rays will create a new file with the patched code and update the database.
If you want to collaborate and share the patched executable files with other reverse engineers, you should consider the compatibility, legality, security, and communication of the files. Hex-Rays supports various file formats, but not all may work on different platforms or systems. Additionally, patching executable files could violate copyright or license agreements. Furthermore, new bugs or vulnerabilities may be introduced that could compromise the integrity or confidentiality of the files. Lastly, patching executable files could change the functionality or behavior of the files and affect the analysis or results of other reverse engineers. To facilitate collaboration and sharing of patched executable files with Hex-Rays, Hex-Rays Cloud is available as a web service. It allows users to upload, download, comment on, view, edit C code online, and apply patches directly from the browser. Plus, users can create projects and invite others to join and contribute. Hex-Rays Cloud is free for personal use but requires registration and logging in.
While cloud software can often offer features you didn't ask for, it's important to note that the desktop version is necessary if the software you're trying to patch is Hex-Rays.