alert dns $HOME_NET any -> any any (msg:"ET INFO DNS Query for Suspicious .cf Domain"; threshold:type limit, count 1, track by_src, seconds 120; dns.query; content:".cf"; nocase; endswith; classtype:misc-activity; sid:2025107; rev:6; metadata:created_at 2017_12_03, confidence Medium, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2022_12_01;)