alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Observed NamelessC2 Domain (namelessserver .com in TLS SNI)"; flow:established,to_server; tls.sni; dotprefix; content:".namelessserver.com"; endswith; fast_pattern; reference:url,github.com/trickster0/NamelessC2/blob/d075534d4be70fed2e0d3f85c8e90ccc7ac5bc85/NamelessImplant/src/lib.rs#L136; classtype:domain-c2; sid:2056362; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, attack_target Client_Endpoint, created_at 2024_09_30, deployment Perimeter, malware_family NamelessC2, performance_impact Low, confidence High, signature_severity Critical, updated_at 2024_09_30, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)