alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET ADWARE_PUP Adware.MultiInstaller checkin 2"; flow:established, to_server; http.method; content:"GET"; http.uri; content:"/entrance?s1="; depth:13; pcre:"/^\/entrance\?s1=[a-f0-9]{100,}$/i"; http.header_names; content:!"Referer|0d 0a|"; reference:md5,c610d46d97c1b80f027f56d227a003f7; classtype:pup-activity; sid:2018590; rev:4; metadata:created_at 2014_06_20, signature_severity Minor, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_08_31;)