Category: Reverse Engineering / Crypto
Points: 450 (mid‑range)
Difficulty: Medium – you need to recognise a custom XOR‑based “encryption” routine and recover the key that is derived from the binary name itself.
Below is a complete, step‑by‑step walk‑through of the challenge, from the initial download to the final flag extraction. Feel free to skim the sections you already know – the core idea is only a few lines of code, but the path to discover it is what makes this problem interesting. vladmodelsy095alina44 2021
$ file vladmodelsy095alina44
vladmodelsy095alina44: ELF 64-bit LSB executable, x86‑64, dynamically linked, stripped
The binary is a stripped 64‑bit ELF. No obvious strings like a flag are present at first glance, but there are a handful of printable strings: Below is a complete, step‑by‑step walk‑through of the
$ strings vladmodelsy095alina44 | head -20
/lib64/ld-linux-x86-64.so.2
GLIBC_2.2.5
...
vladmodelsy095alina44
The binary name itself appears as a string inside the binary. That’s a hint that the name is used somewhere in the program logic. Tips for Aspiring Models in 2021:
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