I'm not sure if this is the right place to post this issue or not. 

I'm trying to protect my Nagios http login from unauthorized attempts. 

I have tried to match what's in the /var/log/apache2/error.log to my regex in /etc/fail2ban/filter.d/apache-auth.conf file, but when I test it, it doesn't return any matches, even though there are unsuccessful attempts in that log. 

Here is my jail.local config file:

# Fail2Ban configuration file.
#
# This file was composed for Debian systems from the original one
#  provided now under /usr/share/doc/fail2ban/examples/jail.conf
#  for additional examples.
#
# To avoid merges during upgrades DO NOT MODIFY THIS FILE
# and rather provide your changes in /etc/fail2ban/jail.local
#
# Author: Yaroslav O. Halchenko <debian@onerussian.com>
#
# $Revision$
#

# The DEFAULT allows a global definition of the options. They can be overridden
# in each jail afterwards.

[DEFAULT]

# "ignoreip" can be an IP address, a CIDR mask or a DNS host
ignoreip = 127.0.0.1/8
bantime  = 600
maxretry = 3

# "backend" specifies the backend used to get files modification. Available
# options are "gamin", "polling" and "auto".
# yoh: For some reason Debian shipped python-gamin didn't work as expected
#      This issue left ToDo, so polling is default backend for now
backend = auto

#
# Destination email address used solely for the interpolations in
# jail.{conf,local} configuration files.
destemail = tyosick@topgunhq.com

#
# ACTIONS
#

# Default banning action (e.g. iptables, iptables-new,
# iptables-multiport, shorewall, etc) It is used to define
# action_* variables. Can be overridden globally or per
# section within jail.local file
banaction = iptables-multiport

# email action. Since 0.8.1 upstream fail2ban uses sendmail
# MTA for the mailing. Change mta configuration parameter to mail
# if you want to revert to conventional 'mail'.
mta = mail

# Default protocol
protocol = tcp

# Specify chain where jumps would need to be added in iptables-* actions
chain = INPUT

#
# Action shortcuts. To be used to define action parameter

# The simplest action to take: ban only
action_ = %(banaction)s[name=%(__name__)s, port="%(port)s", protocol="%(protocol)s", chain="%(chain)s"]

# ban & send an e-mail with whois report to the destemail.
action_mw = %(banaction)s[name=%(__name__)s, port="%(port)s", protocol="%(protocol)s", chain="%(chain)s"]
              %(mta)s-whois[name=%(__name__)s, dest="%(destemail)s", protocol="%(protocol)s", chain="%(chain)s"]

# ban & send an e-mail with whois report and relevant log lines
# to the destemail.
action_mwl = %(banaction)s[name=%(__name__)s, port="%(port)s", protocol="%(protocol)s", chain="%(chain)s"]
               %(mta)s-whois-lines[name=%(__name__)s, dest="%(destemail)s", logpath=%(logpath)s, chain="%(chain)s"]

# Choose default action.  To change, just override value of 'action' with the
# interpolation to the chosen action shortcut (e.g.  action_mw, action_mwl, etc) in jail.local
# globally (section [DEFAULT]) or per specific section
action = %(action_mwl)s

#
# JAILS
#

# Next jails corresponds to the standard configuration in Fail2ban 0.6 which
# was shipped in Debian. Enable any defined here jail by including
#
# [SECTION_NAME]
# enabled = true

#
# in /etc/fail2ban/jail.local.
#
# Optionally you may override any other parameter (e.g. banaction,
# action, port, logpath, etc) in that section within jail.local

[ssh]

enabled  = true
port     = 22
filter   = sshd
logpath  = /var/log/auth.log
maxretry = 2

[dropbear]

enabled  = false
port     = ssh
filter   = sshd
logpath  = /var/log/dropbear
maxretry = 6

# Generic filter for pam. Has to be used with action which bans all ports
# such as iptables-allports, shorewall
[pam-generic]

enabled  = true
# pam-generic filter can be customized to monitor specific subset of 'tty's
filter   = pam-generic
# port actually must be irrelevant but lets leave it all for some possible uses
port     = all
banaction = iptables-allports
port     = anyport
logpath  = /var/log/auth.log
maxretry = 2

[xinetd-fail]

enabled   = false
filter    = xinetd-fail
port      = all
banaction = iptables-multiport-log
logpath   = /var/log/daemon.log
maxretry  = 2


[ssh-ddos]

enabled  = true
port     = ssh
filter   = sshd-ddos
logpath  = /var/log/auth.log
maxretry = 6

#
# HTTP servers
#

[apache]

enabled  = true
port     = 80,443
filter   = apache-auth
logpath  = /var/log/apache2/error.log
maxretry = 2

# default action is now multiport, so apache-multiport jail was left
# for compatibility with previous (<0.7.6-2) releases
[apache-multiport]

enabled   = true
port      = 80,443
filter    = apache-auth
logpath   = /var/log/apache*/*error.log
maxretry  = 2

[apache-noscript]

enabled  = true
port     = 80,443
filter   = apache-noscript
logpath  = /var/log/apache*/*error.log
maxretry = 2

[apache-overflows]

enabled  = true
port     = http,https
filter   = apache-overflows
logpath  = /var/log/apache*/*error.log
maxretry = 2

#
# FTP servers
#

[vsftpd]

enabled  = false
port     = ftp,ftp-data,ftps,ftps-data
filter   = vsftpd
logpath  = /var/log/vsftpd.log
# or overwrite it in jails.local to be
# logpath = /var/log/auth.log
# if you want to rely on PAM failed login attempts
# vsftpd's failregex should match both of those formats
maxretry = 6


[proftpd]

enabled  = false
port     = ftp,ftp-data,ftps,ftps-data
filter   = proftpd
logpath  = /var/log/proftpd/proftpd.log
maxretry = 6


[pure-ftpd]

enabled  = false
port     = ftp,ftp-data,ftps,ftps-data
filter   = pure-ftpd
logpath  = /var/log/auth.log
maxretry = 6


[wuftpd]

enabled  = false
port     = ftp,ftp-data,ftps,ftps-data
filter   = wuftpd
logpath  = /var/log/auth.log
maxretry = 6


#
# Mail servers
#

[postfix]

enabled  = true
port     = smtp,ssmtp
filter   = postfix
logpath  = /var/log/mail.log


[couriersmtp]

enabled  = false
port     = smtp,ssmtp
filter   = couriersmtp
logpath  = /var/log/mail.log


#
# Mail servers authenticators: might be used for smtp,ftp,imap servers, so
# all relevant ports get banned
#

[courierauth]

enabled  = false
port     = smtp,ssmtp,imap2,imap3,imaps,pop3,pop3s
filter   = courierlogin
logpath  = /var/log/mail.log


[sasl]

enabled  = false
port     = smtp,ssmtp,imap2,imap3,imaps,pop3,pop3s
filter   = sasl
# You might consider monitoring /var/log/mail.warn instead if you are
# running postfix since it would provide the same log lines at the
# "warn" level but overall at the smaller filesize.
logpath  = /var/log/mail.log

[dovecot]

enabled = false
port    = smtp,ssmtp,imap2,imap3,imaps,pop3,pop3s
filter  = dovecot
logpath = /var/log/mail.log

# DNS Servers


# These jails block attacks against named (bind9). By default, logging is off
# with bind9 installation. You will need something like this:
#
# logging {
#     channel security_file {
#         file "/var/log/named/security.log" versions 3 size 30m;
#         severity dynamic;
#         print-time yes;
#     };
#     category security {
#         security_file;
#     };
# };
#
# in your named.conf to provide proper logging

# !!! WARNING !!!
#   Since UDP is connection-less protocol, spoofing of IP and imitation
#   of illegal actions is way too simple.  Thus enabling of this filter
#   might provide an easy way for implementing a DoS against a chosen
#   victim. See
#    http://nion.modprobe.de/blog/archives/690-fail2ban-+-dns-fail.html
#   Please DO NOT USE this jail unless you know what you are doing.
#[named-refused-udp]
#
#enabled  = false
#port     = domain,953
#protocol = udp
#filter   = named-refused
#logpath  = /var/log/named/security.log

[named-refused-tcp]

enabled  = false
port     = domain,953
protocol = tcp
filter   = named-refused
logpath  = /var/log/named/security.log

Additionally, here is my apache-auth filter file:

# Fail2Ban configuration file
#
# Author: Cyril Jaquier
#
# $Revision$
#

[INCLUDES]

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

[Definition]

# Option:  failregex
# Notes.:  regex to match the password failure messages in the logfile. The
#          host must be matched by a group named "host". The tag "<HOST>" can
#          be used for standard IP/hostname matching and is only an alias for
#          (?:::f{4,6}:)?(?P<host>[\w\-.^_]+)
# Values:  TEXT
#
failregex = ^%(_apache_error_client)s user .* (authentication failure|not found /nagios3|password mismatch)\s*$
failregex = [error] [[]client <HOST>[]] user .* authentication failure
            [error] \[client <HOST>\] user .* not found: /nagios3/
            [error] []]client <HOST>[]] user .* password mismatch
# Option:  ignoreregex
# Notes.:  regex to ignore. If this regex matches, the line is ignored.
# Values:  TEXT
#

Finally, here is a snippet of an unsuccessful attempt to log in to my Nagios instance from /var/log/apache2/error.log:

 [Mon Feb 17 09:13:03 2014] [error] [client 1.1.1.1] user kjjk not found: /nagios3/
[Mon Feb 17 09:13:07 2014] [error] [client 1.1.1.1] user klklkl not found: /nagios3

As you can see I tried it several times, but fail2ban did not block my IP address. 

Here is a sample test of my regex:

fail2ban-regex /var/log/apache2/error.log /etc/fail2ban/filter.d/apache-auth.conf

Running tests
=============

Use regex file : /etc/fail2ban/filter.d/apache-auth.conf
Use log file   : /var/log/apache2/error.log


Results
=======

Failregex
|- Regular expressions:
|  [1] [error] [[]client <HOST>[]] user .* authentication failure
|  [2] [error] \[client <HOST>\] user .* not found: /nagios3/
|  [3] [error] []]client <HOST>[]] user .* password mismatch
|
`- Number of matches:
   [1] 0 match(es)
   [2] 0 match(es)
   [3] 0 match(es)

Ignoreregex
|- Regular expressions:
|
`- Number of matches:

Summary
=======

Sorry, no match

Look at the above section 'Running tests' which could contain important
information.

I'm sure it's probably something simple. any help would be greatly appreciated! Thanks!

--
Tyler Yosick
IT Support
Top Gun Performance Solutions