alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET USER_AGENTS Suspicious User-Agent (Hello World)"; flow:established,to_server; http.user_agent; bsize:12; content:"Hello World"; nocase; fast_pattern; classtype:trojan-activity; sid:2038507; rev:2; metadata:attack_target Client_Endpoint, created_at 2022_08_12, deployment Perimeter, deployment SSLDecrypt, confidence High, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_03_26, reviewed_at 2024_12_02;)