alert tcp $EXTERNAL_NET $HTTP_PORTS -> $HOME_NET any (msg:"ET MALWARE Night Dragon CnC Traffic Inbound 2"; flow:established,from_server; dsize:16; content:"|68 57 24 13|"; offset:12; depth:4; threshold:type limit, count 1, seconds 60, track by_src; reference:url,www.mcafee.com/us/resources/white-papers/wp-global-energy-cyberattacks-Night-dragon.pdf; classtype:command-and-control; sid:2012305; rev:5; metadata:created_at 2011_02_10, signature_severity Major, updated_at 2019_07_26;)