alert tcp $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Backdoor.Win32.Xyligan Checkin"; flow:to_server,established; dsize:16; content:"|00 00 00 11 C8 00 00 00|"; depth:8; reference:md5,2190a2c0a3775bc9c60629ec2eb6f3b9; reference:md5,bfbc0b106a440c111a42936906d36643; classtype:command-and-control; sid:2012842; rev:3; metadata:created_at 2011_05_25, confidence Medium, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)