ghidra-scripts VS CyberChef

I've got no experience with reverse-engineering executables, but I got a bunch of code-like stuff showing up when I fed ULTIMA.EXE to Ghidra and told it to analyze it with all the flags set.

The whole game is written in C++ (game logic intertwined with graphics). Ghidra can help you deconstruct the game binaries, but you need to put in a GREAT great effort to even get a starting point. Cheat Engine has been successful for some purposes, including an AI enabling utility for multiplayer (use with great care!).

Ghidra: https://ghidra-sre.org/, https://github.com/NationalSecurityAgency/ghidra

What I think you’re talking about is reverse engineering. It’s basically taking a program and analysing the compiled code to attempt to find out how it works. It’s a fairly expansive topic, and fairly tricky to do but look at anything to do with Ghidra to get started.

Oh also just as an aside Ghidra is a really cool free tool developed by the NSA which can reverse engineer software by looking at its executable and recreating the C code from the instructions and static data within. It's another way to get familiarized with the relationship between C code and the instructions it compiles to.

There exist decompilers and other tools for helping make sense of assembly and that can automate some of the conversion back to higher level languages. In my brief involvement with Slippi I used Ghidra - a tool developed by the NSA, to do some of that kind of work, which I found a little amusing.

It's likely a binary file that's improperly being interpreted as Unicode by the text editor. If it's an executable file, you can use Ghidra to disassemble and analyze it. There may also be some interesting ASCII strings that would reveal its purpose. My guess is that it's a Windows version of Unix "tee" program which will write stdin to a file and stdout simultaneously.

On the other hand, this slick "Ghidra" webpage looks suspicious. It's probably written in Typescript on Electron!

Then we take the encrypted text and use CyberChef to decrypt it.

Let's go to CyberChef and insert our pieces of evidence.

A parameter was changed from '2AMBCgIQBg' to 'CgIIAdgDAQ%3D%3D' which is just the correct base64 encoding they should have been using the entire time.

I don't think this was a hostile action by Google, I think someone just added better input validation for security reasons and it accidently broke the bad requests they were sending.

https://gchq.github.io/CyberChef/#recipe=URL_Decode()From_Ba...

❗This is indeed the flag, but the text is encrypted with Base64. Usually, the presence of padding character "=" indicates that's Base64 type of encoding (but that's only one of the hints). To decrypt it, we can use CyberChef. Copy-paste the text and we either:

It uses a combination of magic bytes (like the `file` command), entropy analysis and character frequency detection to determine whether an output is likely to be of interest to the user.

The file type mechanism is written here[0]. There's a list of all signatures we detect here[1].

[0] https://github.com/gchq/CyberChef/blob/master/src/core/lib/F...

I think this can be deciphered using CyberChef...