alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET POLICY External IP Lookup - checkip.dyndns.org"; flow:established,to_server; http.host; content:"checkip.dyndns.org"; fast_pattern; depth:18; endswith; classtype:external-ip-check; sid:2021378; rev:7; metadata:attack_target Client_Endpoint, created_at 2015_07_02, 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;)