Tools to help reverse engineer binary file formats

Question

What tools are available to aid in decoding unknown binary data formats?

I know Hex Workshop and 010 Editor both support structures. These are okay

Answer 1

My own tool "iBored", which I released just recently, can do parts of this. I wrote the tool to visualize and debug file system formats (UDF, HFS, ISO9660, FAT etc.), and implemented search, copy and later even structure and templates support. The structure support is pretty straight-forward, and the templates are a way to identify structures dynamically.

The entire thing is programmable in a Visual BASIC dialect, allowing you to test values, read specific blocks, and all.

The tool is free, works on all platforms (Win, Mac, Linux), but as it's personal tool which I just released to the public to share it, it's not much documented.

However, if you want to give it a try, and like to give feedback, I might add more useful features.

I'd even open source it, but as it's written in REALbasic, I doubt many people will join such a project.

Link: iBored home page

Answer 2

I still occasionally use an old hex editor called A.X.E., Advanced Hex Editor. It seems to have largely disappeared from the Internet now, though Google should still be able to find it for you. The last version I know of was version 3.4, but I've really only used the free-for-personal-use version 2.1.

Its most interesting feature, and the one I've had the most use for deciphering various game and graphics formats, is its graphical view mode. That basically just shows you the file with each byte turned into a color-coded pixel. And as simple as that sounds, it has made my reverse-engineering attempts a lot easier at times.

I suppose doing it by eye is quite the opposite of doing automatic analysis, though, and the graphical mode won't be much use for finding and following offsets...

The later version has some features that sound like they could fit your needs (scripts, regularity finder, grammar generator), but I have no idea how good they are.