alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Sakula/Mivast RAT CnC Beacon 1"; flow:established,to_server; http.uri; content:".asp?imageid="; fast_pattern; http.header_names; content:!"Content-Type"; content:!"Accept-"; content:!"Referer"; reference:md5,3cd598e8e2fd033134d8784251eff59e; classtype:command-and-control; sid:2016139; rev:6; metadata:attack_target Client_Endpoint, created_at 2013_01_03, deployment Perimeter, signature_severity Major, tag c2, updated_at 2020_08_18, mitre_tactic_id TA0010, mitre_tactic_name Exfiltration, mitre_technique_id T1041, mitre_technique_name Exfiltration_Over_C2_Channel;)