alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Poweliks Clickfraud CnC M4"; flow:to_server,established; http.method; content:"GET"; http.uri; content:"click?sid="; fast_pattern; content:"&cid="; distance:0; pcre:"/\?sid=[a-f0-9]{40}&cid=[0-9]$/"; http.header_names; content:"Referer|0d 0a|"; reference:url,www.symantec.com/content/en/us/enterprise/media/security_response/whitepapers/evolution-of-poweliks.pdf; reference:md5,e13234077f513208238203108df30ff4; classtype:command-and-control; sid:2021251; rev:4; metadata:created_at 2015_06_11, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_06_16;)