alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Observed TA453 Related Domain in TLS SNI"; flow:established,to_server; tls.sni; bsize:22; content:"defaultbluemarker.info"; fast_pattern; reference:url,www.volexity.com/blog/2024/02/13/charmingcypress-innovating-persistence/; classtype:domain-c2; sid:2052407; rev:1; metadata:attack_target Client_Endpoint, created_at 2023_10_17, deployment Perimeter, malware_family TA453, performance_impact Low, confidence High, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2024_05_06, reviewed_at 2024_03_18, former_sid 2855366, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1071, mitre_technique_name Application_Layer_Protocol;)