alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET INFO External IP Lookup - ip.tyk.nu"; flow:established,to_server; urilen:1; http.host; bsize:9; content:"ip.tyk.nu"; fast_pattern; classtype:external-ip-check; sid:2022368; rev:7; metadata:attack_target Client_Endpoint, created_at 2016_01_14, 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;)