alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET USER_AGENTS Suspicious User-Agent (NSIS_DOWNLOAD)"; flow:to_server,established; threshold:type limit,count 2,track by_src,seconds 300; http.user_agent; content:"NSIS_DOWNLOAD"; nocase; depth:13; classtype:pup-activity; sid:2008216; rev:11; 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_16;)