alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET ADWARE_PUP YourSiteBar User-Agent (istsvc)"; flow:to_server,established; http.user_agent; content:"istsvc"; nocase; depth:6; endswith; reference:url,www.ysbweb.com; classtype:pup-activity; sid:2001699; rev:264; metadata:created_at 2010_07_30, confidence High, signature_severity Minor, updated_at 2020_10_17;)