alert tcp $SQL_SERVERS 3306 -> $EXTERNAL_NET any (msg:"ET ATTACK_RESPONSE MySQL User Account Enumeration"; flow:from_server,established; content:"|02|"; offset:3; depth:4; content:"|15 04|Access denied for user"; fast_pattern; threshold:type both,track by_dst,count 10,seconds 1; reference:url,seclists.org/fulldisclosure/2012/Dec/att-9/; classtype:protocol-command-decode; sid:2015993; rev:3; metadata:created_at 2012_12_06, signature_severity Minor, updated_at 2019_10_08;)