Rule History

alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Observed TA399/Sidewinder APT Domain (defencelk .cvix .live in TLS SNI)"; flow:established,to_server; tls.sni; dotprefix; content:".defencelk.cvix.live"; endswith; fast_pattern; reference:md5,43d35b5b20f491be219ab2eaa172ec55; classtype:trojan-activity; sid:2055186; rev:2; metadata:attack_target Client_Endpoint, created_at 2024_08_08, deployment Perimeter, deprecation_reason Age, confidence High, signature_severity Major, tag Sidewinder, tag TA399, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2025_04_15, reviewed_at 2025_04_15, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)