alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Unkown Trojan User-Agent (5.1 ...)"; flow:established,to_server; http.user_agent; content:"5.1 "; startswith; classtype:trojan-activity; sid:2009685; rev:7; metadata:created_at 2010_07_30, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_03_01;)