Hello
I am using Almalinux Version 8.10, Exim version, Fail2Ban v1.0.2 and exim Exim version 4.98 #2 built 04-Oct-2024 15:50:54. There is a issue with the /etc/fail2ban/filter.d/exim.cong that is included in the Almalinux distrubution and it’s not detecting the incoming smtp mail connections. Can someone please provide me with a failregex that works?
I have already talked to the fail2ban developers and they told me to come and ask you.
Thanks
Phil Taylor
more exim.conf
# Fail2Ban filter for exim
#
# This includes the rejection messages of exim. For spam and filter
# related bans use the exim-spam.conf
#
[INCLUDES]
# Read common prefixes. If any customizations available -- read them from
# exim-common.local
before = exim-common.conf
[Definition]
# Fre-filter via "prefregex" is currently inactive because of too different failure syntax in exim-log (testing needed):
#prefregex = ^%(pid)s <F-CONTENT>\b(?:\w+ authenticator failed|([\w\-]+ )?SMTP (?:(?:call|connection) from|protocol(?: s
ynchronization)? error)|no MAIL in|(?:%(host_info_pre)s\[[^\]]+\]%(host_info_suf)s(?:sender verify fail|rejected RCPT|dr
opped|AUTH command))).+</F-CONTENT>$
failregex = ^%(pid)s %(host_info)ssender verify fail for <\S+>: (?:Unknown user|Unrouteable address|all relevant MX reco
rds point to non-existent hosts)\s*$
^%(pid)s \w+ authenticator failed for (?:[^\[\( ]* )?(?:\(\S*\) )?\[<HOST>\](?::\d+)?(?: I=\[\S+\](:\d+)?)?:
535 Incorrect authentication data( \(set_id=.*\)|: \d+ Time\(s\))?\s*$
^%(pid)s %(host_info)srejected RCPT [^@]+@\S+: (?:relay not permitted|Sender verify failed|Unknown user|Unro
uteable address)\s*$
^%(pid)s SMTP protocol synchronization error \([^)]*\): rejected (?:connection from|"\S+") %(host_info)s(?:n
ext )?input=".*"\s*$
^%(pid)s SMTP call from (?:[^\[\( ]* )?%(host_info)sdropped: too many (?:nonmail commands|syntax or protocol
errors) \(last (?:command )?was "[^"]*"\)\s*$
^%(pid)s SMTP protocol error in "[^"]+(?:"+[^"]*(?="))*?" %(host_info)sAUTH command used when not advertised
\s*$
^%(pid)s no MAIL in SMTP connection from (?:[^\[\( ]* )?(?:\(\S*\) )?%(host_info)sD=\d\S*s(?: C=\S*)?\s*$
^%(pid)s (?:[\w\-]+ )?SMTP connection from (?:[^\[\( ]* )?(?:\(\S*\) )?%(host_info)sclosed by DROP in ACL\s*
$
<mdre-<mode>>
mdre-aggressive = ^%(pid)s no host name found for IP address <HOST>$
^%(pid)s no IP address found for host \S+ \(during SMTP connection from \[<HOST>\]\)$
mdre-normal =
# Parameter `mode` - `normal` or `aggressive`.
# Aggressive mode can be used to match flood and ddos-similar log-entries like:
# 'no host found for IP', 'no IP found for host'.
# Note this is not an authentication failures, so it may produce lots of false
# positives on misconfigured MTAs.
# Ex.:
# filter = exim[mode=aggressive]
mode = normal
ignoreregex =
# DEV Notes:
# The %(host_info) defination contains a <HOST> match
#
# SMTP protocol synchronization error \([^)]*\) <- This needs to be non-greedy
# to void capture beyond ")" to avoid a DoS Injection vulnerabilty as input= is
# user injectable data.
#
# Author: Cyril Jaquier
# Daniel Black (rewrote with strong regexs)
# Martin O'Neal (added additional regexs to detect authentication failures, protocol errors, and drops)