alert dns any any -> $HOME_NET any (msg:"ET DNS Reply Sinkhole - German Company"; content:"|00 01 00 01|"; content:"|00 04 52 a5 19 a7|"; distance:4; within:6; reference:url,virustracker.info; classtype:trojan-activity; sid:2016420; rev:7; metadata:created_at 2013_02_16, confidence High, signature_severity Informational, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2022_07_13;)