alert tcp $EXTERNAL_NET $HTTP_PORTS -> $HOME_NET any (msg:"ET MALWARE Koobface BLACKLABEL"; flow:established,from_server; content:"#BLACKLABEL|0d 0a|EXIT"; reference:url,blog.threatexpert.com/2008/12/koobface-leaves-victims-black-spot.html; classtype:trojan-activity; sid:2009407; rev:2; metadata:created_at 2010_07_30, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2019_07_26;)