alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET USER_AGENTS Suspicious User-Agent (aaaa)"; flow:established,to_server; http.user_agent; content:"aaaa"; bsize:4; reference:md5,61e213e717cc8e156cec79a7c1cd0c64; classtype:bad-unknown; sid:2031613; rev:1; metadata:attack_target Client_Endpoint, created_at 2021_02_11, deployment Perimeter, confidence High, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2021_02_11;)