binculator

spbctf

Task: server streams 10 base64-encoded 32-bit x86 ELF DFA validators, each needing an accepting input string within 120s. Solution: built a generic solver that emulates only init_states() with Unicorn (PLT/malloc hooked), extracts the per-binary accept marker via capstone, reconstructs the DFA graph in emulated memory, and BFS-finds the shortest accepting string.