alert udp any 53 -> $HOME_NET any (msg:"ET MALWARE Possible Emotet DGA NXDOMAIN Responses"; byte_test:1,&,128,2; byte_test:1,&,1,3; byte_test:1,&,2,3; content:"|00 01 00 00 00 01|"; offset:4; depth:6; content:"|02|eu|00|"; distance:19; within:4; fast_pattern; content:"|10|"; distance:-21; within:1; pcre:"/^[a-z]{16}/R"; threshold:type both, track by_src, count 12, seconds 120; reference:md5,3083b68cb5c2a345972a5f79e735c7b9; classtype:trojan-activity; sid:2019692; rev:1; metadata:created_at 2014_11_12, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)