alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Win32/Sefnit Initial Checkin"; flow:established,to_server; http.uri; content:"/version.php?ver="; content:"&app="; http.user_agent; content:"NSISDL"; startswith; classtype:command-and-control; sid:2013221; rev:4; metadata:created_at 2011_07_06, malware_family Win32_Sefnit, signature_severity Major, updated_at 2024_03_08;)