CatGirl Industrials Shell

spbctf

Task: reverse a custom self-modifying stack VM written in pure Python that validates a password in 5 blocks; a _rerere_ opcode assembles a second-stage validator at runtime, blocking static analysis. Solution: derive the opcode semantics from the dispatch loop, emulate the VM (patching a seed() crash), dump the self-built stage-2 slot map, and invert each block's transform (equality, reversed-list, XOR 0x24, exact-string, base64url+ord-sum) to recover REDACTED.