alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE VirRansom/VirLock Checkin"; flow:established,to_server; dsize:4; content:"|94 00 00 00|"; fast_pattern; flowbits:set,ET.VirLock; flowbits:noalert; reference:md5,fbeb6ebd498d85b1f404d7bb4acc3b89; classtype:command-and-control; sid:2019901; rev:2; metadata:created_at 2014_12_10, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_10_08;)