alert http $EXTERNAL_NET any -> $HOME_NET any (msg:"ET MALWARE Backdoor.Win32.Likseput.B Checkin 2"; flow:from_server,established; file_data; content:"|3c 21 2d 2d 0d 0a 3c|img border="; nocase; content:"|2f 23|KX8|2E|"; distance:5; within:64; fast_pattern; pcre:"/^\x3c\x21\x2d\x2d\x0d\x0a\x3cimg\x20border=\d+\x20src=\x22\S+\x2f\x23KX8\x2e/mi"; reference:url,www.microsoft.com/security/portal/Threat/Encyclopedia/Entry.aspx?Name=Backdoor%3aWin32%2fLikseput.B; classtype:command-and-control; sid:2016428; rev:7; metadata:created_at 2011_03_08, confidence Medium, signature_severity Major, updated_at 2019_07_26;)