fail2ban/config/filter.d/mysqld-auth.conf

# Fail2Ban filter for unsuccesful MySQL authentication attempts
#
#
# To log wrong MySQL access attempts add to /etc/my.cnf in [mysqld]:
# log-error=/var/log/mysqld.log
# log-warnings = 2
#
# If using mysql syslog [mysql_safe] has syslog in /etc/my.cnf

[INCLUDES]

# Read common prefixes. If any customizations available -- read them from
# common.local
before = common.conf

[Definition]

_daemon = mysqld

failregex = ^%(__prefix_line)s(?:(?:\d{6}|\d{4}-\d{2}-\d{2})[ T]\s?\d{1,2}:\d{2}:\d{2} )?(?:\d+ )?\[\w+\] (?:\[[^\]]+\] )*Access denied for user '<F-USER>[^']+</F-USER>'@'<HOST>' (to database '[^']*'|\(using password: (YES|NO)\))*\s*$

ignoreregex = 

# DEV Notes:
#
# Technically __prefix_line can equate to an empty string hence it can support
# syslog and non-syslog at once.
# Example:
# 130322 11:26:54 [Warning] Access denied for user 'root'@'127.0.0.1' (using password: YES)
#
# Authors: Artur Penttinen
#          Yaroslav O. Halchenko