alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET USER_AGENTS Suspicious User-Agent (App4)"; flow:to_server,established; threshold:type limit, count 2, track by_src, seconds 300; http.user_agent; content:"App"; depth:3; fast_pattern; pcre:"/^\d/R"; http.host; content:!"liveupdate.symantecliveupdate.com"; classtype:trojan-activity; sid:2008073; rev:16; metadata:affected_product Any, attack_target Client_Endpoint, created_at 2010_07_30, deployment Perimeter, confidence High, signature_severity Major, tag User_Agent, updated_at 2020_08_17;)