Themida Unpacking: One Breakpoint, Zero Execution
Introduction
Have you ever wondered if you could unpack a Themida-protected binary without actually running any of its code? Well, it turns out you can—using just a single hardware breakpoint. Yes, you read that right. It’s simple, effective, and didn’t involve summoning any dark reverse engineering rituals. This method was tested on Themida version 3.0.4.0, and it should work on newer versions too.
The Magic: Unpacking
First thing's first: you need to disable the anti-debugging features in Themida. Enter ScyllaHide, a trusty tool that bypasses them, allowing us to continue without interference.
Now comes the fun part: setting a hardware breakpoint on the .text section of the binary. This section is usually the first one in the PE file. Once the breakpoint is set, simply run the executable. It won’t execute anything—it’ll just hit the breakpoint immediately. Magic!
Voilà! The binary is now unpacked, and its Import Address Table (IAT) has been fully restored—without executing a single line of code. The unpacked binary is ready for further analysis, or perhaps some harmless tweaking.
The Before and After: Packed vs Unpacked
Here's a quick visual comparison of the binary before and after unpacking:
Packed Binary
Unpacked Binary
Conclusion
So there you have it—an efficient, straightforward method to unpack Themida-protected binaries using just one breakpoint. Whether you're delving into reverse engineering or analyzing malware, this technique allows you to explore the binary's contents without executing potentially dangerous code. Happy reversing!
Acknowledgments
A huge shoutout to x64dbg and ScyllaHide for providing the tools that made this unpacking method possible.