Reversing as an Art

Notes on RCE fun.

Flare-On Challenge III Solution

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This challenge is about analyzing a binary file. Let’s load it into IDA. What we see here is a sort of “obfuscation” where the actual code (payload) is moved into the stack by the loader and executed from there:

The payload is actually a multi-stage xor based, self decrypting code which in our case has various funny sentences revealed in every decrypted part:

Stage Result

I hope, you’ve got the idea here. I’ll omit several stages and come straight to the last meaningful stage where the email we’ve been looking for is revealed: