alert dns $HOME_NET any -> any any (msg:"ET INFO Proxy Service Domain in DNS Lookup (proxyjet .io)"; dns.query; dotprefix; content:".proxyjet.io"; nocase; endswith; reference:url,cloud.google.com/blog/topics/threat-intelligence/disrupting-largest-residential-proxy-network; classtype:misc-activity; sid:2068315; rev:1; metadata:attack_target Client_Endpoint, created_at 2026_03_18, deployment Perimeter, confidence High, signature_severity Informational, tag Residential_Proxy_Service, tag Description_Generated_By_Proofpoint_Nexus, tag VPN_Services, updated_at 2026_03_18, mitre_tactic_id TA0011, mitre_tactic_name Command_And_Control, mitre_technique_id T1572, mitre_technique_name Protocol_Tunneling;)