alert http $EXTERNAL_NET any -> $HTTP_SERVERS any (msg:"ET MALWARE VBulletin Backdoor CMD inbound"; flow:established,to_server; http.header; content:"HTTP_ECMDE|3a|"; reference:url,blog.sucuri.net/2013/07/vbulletin-infections-from-adabeupdate.html; classtype:trojan-activity; sid:2017111; rev:5; metadata:created_at 2013_07_05, signature_severity Major, tag Description_Generated_By_Proofpoint_Nexus, updated_at 2020_04_24;)