alert dns $HOME_NET any -> any any (msg:"ET INFO DNS Query for Suspicious .icu Domain"; threshold:type limit, count 1, track by_src, seconds 120; dns.query; content:".icu"; nocase; endswith; classtype:bad-unknown; sid:2026888; rev:4; metadata:attack_target Client_Endpoint, created_at 2019_02_06, deployment Perimeter, confidence Medium, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2022_11_21;)