alert tcp $HOME_NET any -> $EXTERNAL_NET 1024: (msg:"ET MALWARE Donbot Connect to CnC"; flow:established,to_server; dsize:7; content:"HALLO|0d 0a|"; depth:7; reference:url,blog.fireeye.com/research/2009/10/a-little_more_on_donbot.html; reference:url,www.avertlabs.com/research/blog/index.php/2009/04/05/donbot-joining-the-club-of-million-dollar-botnets/; classtype:command-and-control; sid:2008450; rev:5; metadata:created_at 2010_07_30, signature_severity Major, updated_at 2019_07_26;)