ShadowSocks(SS) traffic sniffer
ShadowSocks(SS) traffic sniffer
Proof of concept of detecting SS traffic. Could be used for the improvement of SS. Or, for the censorship against SS. Either way, it is better to expose the vulnerabilities in advance and take the initiative.
# install libpcap first, then pip install -r requirements.txt sudo ./sssniff.py
Finally, browse the web via your SS proxy. When the script detects more than 15 suspicious connections to/from one source, it will flag it to be a ShadowSocks server and print to the terminal.
ShadowSocks is famous for its randomness feature; however, the first packet of a connection is usually not expected to be random. Even in a TLS session, we expect to see some plaintext sections in the handshake stage. Therefore, one can detect ShadowSocks traffic by simply looking at the first few packets and calculating their entropy (as a measure of randomness). Together with some minor adjustments, this method suffices to detect the current ShadowSocks protocol at a high accuracy.