alert tcp $EXTERNAL_NET 443 -> $HOME_NET any (msg:"ET MALWARE Malicious SSL Cert (KINS C2)"; flow:established,from_server; content:"|55 04 03|"; content:"|0f|terriblekira.su"; distance:1; within:16; reference:md5,f752cfdc6aa1d3eac013201357ada0f6; classtype:domain-c2; sid:2021031; rev:1; metadata:attack_target Client_and_Server, created_at 2015_04_30, deployment Perimeter, performance_impact Low, confidence Medium, signature_severity Major, tag SSL_Malicious_Cert, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)