alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET INFO Observed RMM Domain in TLS SNI ( * .action1 .com)"; flow:established,to_server; tls.sni; dotprefix; content:".action1.com"; endswith; fast_pattern; reference:url,attack.mitre.org/techniques/T1219/; classtype:misc-activity; sid:2063861; rev:1; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, affected_product Windows_11, affected_product Windows_8, affected_product Windows_10, affected_product Action1, attack_target Client_and_Server, created_at 2025_07_31, deployment Perimeter, performance_impact Low, confidence High, signature_severity Informational, tag RAT, tag RemoteAccessTool, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2025_07_31, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1219, mitre_technique_name Remote_Access_Software;)