alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET INFO Observed Teleport Service Domain (goteleport .com) in TLS SNI"; flow:established,to_server; tls.sni; dotprefix; content:".goteleport.com"; endswith; fast_pattern; reference:url,www.goteleport.com; classtype:misc-activity; sid:2062131; rev:1; metadata:affected_product Any, attack_target Client_Endpoint, created_at 2025_05_06, deployment Perimeter, performance_impact Low, confidence High, signature_severity Informational, tag proxy_services, updated_at 2025_05_06, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1572, mitre_technique_name Protocol_Tunneling;)