alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET INFO External IP Lookup - ipleak .net"; flow:established,to_server; http.method; content:"GET"; http.host; content:"ipleak.net"; endswith; fast_pattern; http.header_names; to_lowercase; content:!"|0d 0a|referer|0d 0a|"; classtype:misc-activity; sid:2072063; rev:1; metadata:attack_target Client_Endpoint, tls_state TLSDecrypt, created_at 2026_09_17, deployment Perimeter, performance_impact Low, confidence High, signature_severity Informational, updated_at 2026_09_17, mitre_tactic_id TA0043, mitre_tactic_name Reconnaissance, mitre_technique_id T1590, mitre_technique_name Gather_Victim_Network_Information;)