PaloAlto CTF 2017 : Binary Challenge 2
The challenge compute flag using time received from NIST Internet Time Servers and then send computed flag to " labytime.com " server for verification. Before forming flag by using time received from NIST Internet Time Servers the 2nd digit of seconds in received time is set to 0. We have 10 secs to send the computed flag to " labytime.com " server to get correct flag. Re-implemented the logic in python to calculate flag and sending it to " labytime.com " server and reading response to get flag.Below is the python implementation. from rotate import __ROR__ import hashlib import socket import requests c = [0x0C,0x74,0x0C,0x74,0x8D,0x39,0x39,0xED,0x35,0x5D,0x41,0x91,0x39,0x0D,0x15,0x45,0x8D,0x41,0x1D,0x81,0x1D,0x39,0x35,0x31,0x15,0xD9,0x35,0xDD,0x45,0x0C,0x74,0x0C,0x74,0x0C] ror_n = len(c) & 7 decode_str = '' for i in range(0,len(c)): v = __ROR__((c[i]),2) & 0xFF #print hex(v) v = (v ^ len(c))& 0xF...