alert tls $HOME_NET any -> $EXTERNAL_NET any (msg:"ET INFO Observed External IP Lookup Domain in TLS SNI (api .myip .com)"; flow:established,to_server; tls.sni; content:"api.myip.com"; bsize:12; classtype:external-ip-check; sid:2042969; rev:3; metadata:affected_product Any, attack_target Client_Endpoint, created_at 2020_10_29, deployment Perimeter, performance_impact Low, confidence High, signature_severity Informational, updated_at 2024_11_26, former_sid 2845225, mitre_tactic_id TA0007, mitre_tactic_name Discovery, mitre_technique_id T1614, mitre_technique_name System_Location_Discovery;)