alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Observed Malicious Domain (nidnaver .help in TLS SNI)"; flow:established,to_server; tls.sni; bsize:13; content:"nidnaver.help"; fast_pattern; reference:url,www.genians.co.kr/blog/nation-state; classtype:trojan-activity; sid:2051061; rev:1; metadata:attack_target Client_Endpoint, created_at 2024_02_22, deployment Perimeter, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_02_22, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)