alert http $HOME_NET any -> $EXTERNAL_NET any (msg:"ET MALWARE Backdoor.Win32.Xtrat Checkin 2"; flow:to_server,established; http.uri; content:"/1234.functions"; reference:md5,fea70e818984b82c9a6bbdc5157d4a40; reference:url,www.microsoft.com/security/portal/Threat/Encyclopedia/Entry.aspx?Name=Backdoor%3aWin32%2fXtrat.A; classtype:command-and-control; sid:2016599; rev:5; metadata:created_at 2012_10_26, signature_severity Major, updated_at 2020_04_23;)