alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET USER_AGENTS Suspicious User-Agent (update)"; flow:to_server,established; threshold:type limit, count 3, seconds 300, track by_src; http.user_agent; content:"update"; depth:6; endswith; classtype:pup-activity; sid:2003583; rev:14; metadata:affected_product Any, attack_target Client_Endpoint, created_at 2010_07_30, deployment Perimeter, confidence High, signature_severity Minor, tag User_Agent, updated_at 2020_10_19;)