diff --git a/lab8/solve.py b/lab8/solve.py index 9ab3ee2..95fd329 100755 --- a/lab8/solve.py +++ b/lab8/solve.py @@ -1,11 +1,33 @@ #!/usr/bin/env python3 -import angr,sys +import sys +import angr +import claripy + def main(): - secret_key = b"" - sys.stdout.buffer.write(secret_key) + project = angr.Project('./chal', auto_load_libs=False) + + input_len = 8 + chars = [claripy.BVS(f'c{i}', 8) for i in range(input_len)] + buf = claripy.Concat(*chars, claripy.BVV(0, 8)) + + state = project.factory.entry_state(stdin=buf) + + for c in chars: + state.solver.add(c >= 0x20, c <= 0x7e) + + simgr = project.factory.simgr(state) + simgr.explore( + find=lambda s: b"CTF{" in s.posix.dumps(1), + avoid=lambda s: b"Wrong key" in s.posix.dumps(1) + ) + if simgr.found: + sol = simgr.found[0].solver.eval(buf, cast_to=bytes) + print(sol.decode(), end='') + else: + print("No solution found.", end='') if __name__ == '__main__': main()