alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE W32/Siggen.Dropper CnC Beacon"; flow:established,to_server; http.uri; content:".jpg?log="; fast_pattern; content:"&ts="; offset:11; content:"&act="; distance:0; http.header; content:"client|3a 20|"; http.header_names; content:!"Referer|0d 0a|"; reference:md5,ee363de2168aab353c829434189350e4; classtype:command-and-control; sid:2019515; rev:4; metadata:attack_target Client_Endpoint, created_at 2014_10_27, deployment Perimeter, signature_severity Major, tag c2, updated_at 2020_09_25, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)