alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET DELETED External IP Lookup - whoer.net"; flow:established,to_server; content:"Host|3a 20|whoer.net|0d 0a|"; http_header; content:!"Referer|3a|"; http_header; classtype:external-ip-check; sid:2021161; rev:4; metadata:attack_target Client_Endpoint, created_at 2015_05_29, deployment Perimeter, performance_impact Low, confidence High, signature_severity Informational, updated_at 2024_11_26, mitre_tactic_id TA0007, mitre_tactic_name Discovery, mitre_technique_id T1614, mitre_technique_name System_Location_Discovery;)