alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET USER_AGENTS Suspicious User-Agent (MSIE)"; flow:to_server,established; threshold:type limit, count 2, track by_src, seconds 300; http.user_agent; content:"MSIE"; depth:4; http.host; content:!"www.msftncsi.com"; classtype:trojan-activity; sid:2003657; rev:19; 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_18;)