alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Cobalt Strike Related Domain in TLS SNI (safe-dns .it .com)"; flow:established,to_server; tls.sni; bsize:15; content:"safe-dns.it.com"; fast_pattern; reference:url,securelist.com/notepad-supply-chain-attack/118708/; classtype:trojan-activity; sid:2067282; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, affected_product Notepad__, attack_target Client_Endpoint, created_at 2026_02_03, deployment Perimeter, malware_family Cobalt_Strike, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2026_02_03, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)