alert tls $HOME_NET any -> $EXTERNAL_NET 443 (msg:"ET POLICY Possible External IP Lookup Domain Observed in SNI (ipinfo. io)"; flow:established,to_server; tls.sni; content:"ipinfo.io"; bsize:9; fast_pattern; classtype:external-ip-check; sid:2025331; rev:5; metadata:affected_product Windows_XP_Vista_7_8_10_Server_32_64_Bit, affected_product Mac_OSX, affected_product Linux, attack_target Client_Endpoint, created_at 2018_02_07, deployment Perimeter, performance_impact Low, confidence High, signature_severity Informational, updated_at 2024_09_19, mitre_tactic_id TA0007, mitre_tactic_name Discovery, mitre_technique_id T1614, mitre_technique_name System_Location_Discovery;)