reversePromedium

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grodno_new_year_2026

Task: ELF binary with anti-debug protection that encrypts a flag using XOR with position-dependent key and ROL-3 bit rotation. Solution: Reversed the algorithm (ROR-3 then XOR with 0x67+i), discovered a SAR vs SHR compiler bug that broke verification, and patched the binary to confirm the correct decrypted flag.

$ ls tags/ techniques/
xorelfrolsar_vs_shranti_debugptracebinary_patching
static_analysisalgorithm_reversalbug_exploitationbinary_patching
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