alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET POLICY External IP Lookup ipinfo.io"; flow:established,to_server; http.host; content:"ipinfo.io"; depth:9; endswith; fast_pattern; http.header_names; content:!"Referer"; classtype:external-ip-check; sid:2020716; rev:8; metadata:attack_target Client_Endpoint, created_at 2015_03_20, deployment Perimeter, performance_impact Low, confidence High, signature_severity Informational, updated_at 2024_11_26, reviewed_at 2024_03_27, mitre_tactic_id TA0007, mitre_tactic_name Discovery, mitre_technique_id T1614, mitre_technique_name System_Location_Discovery;)