alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Guagua Trojan Update Checkin"; flow:established,to_server; http.uri; content:"/update_check?version="; http.user_agent; content:"Update"; startswith; classtype:command-and-control; sid:2013259; rev:4; metadata:created_at 2011_07_13, signature_severity Major, updated_at 2024_02_07;)