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Zmauditswatch is a ZCS service that notifies the administrator (through any pre-defined e-mail address) of a potential brute force attack for any account hosted by Zimbra by looking at the authentication failure information. Thresholds can be configured per account, IP and account & IP.

Script Options Explanation

The script ships with 4 authentication failure checks.

  • (zimbra_swatch_ipacct_threshold) - IP/Account hash check which warns on 10 auth failures from an IP/Account combo within a 60 second window.
  • (zimbra_swatch_acct_threshold) - Account check which warns on 15 auth failures from any IP within a 60 second window. Attempts to detect a distributed hijack based attack on a single account.
  • (zimbra_swatch_ip_threshold) - IP check which warns on 20 auth failures to any account within a 60 second windows. Attempts to detect a single host based attack across multiple accounts.
  • (zimbra_swatch_total_threshold) - Total auth failure check which warns on 1000 auth failures from any IP to any account within 60 seconds. The recommended value on this is guestimated at 1% of active accounts for the Mailbox.
  • (zimbra_swatch_notice_user) - The email address that we want to be worn when all the conditions happens.

Default values

The default values of zmauditswatch are the next:



zmauditswatch should be run by the user "zimbra". For use zmauditswatch we need to configure it first. The only required configuration is zimbra_swatch_notice_user. The other parameters will use defaults if unspecified.

zmlocalconfig -e

You can change any of this numbers for accommodate to your environment:

zmlocalconfig -e zimbra_swatch_ipacct_threshold=10
zmlocalconfig -e zimbra_swatch_acct_threshold=15
zmlocalconfig -e zimbra_swatch_ip_threshold=20
zmlocalconfig -e zimbra_swatch_total_threshold=60
zmlocalconfig -e zimbra_swatch_threshold_seconds=3600


zmauditswatch is very easy to activate once we configured everything, we just need to start the script:

zmauditswatchctl start

We can stop it

zmauditswatchctl stop

Show the status

zmauditswatchctl status

Workaround for ZCS 8.7.x

Starting Zimbra Collaboration 8.7, parts of the script was moved to another name, which leaded to an error while activating the zmauditswatch, please follow this steps after all the previous configuration ones, plus the zmauditswatchctl start:

as root user

mv attachment.cgi\?id\=66723 auditswatch
mv auditswatch  /opt/zimbra/libexec/auditswatch
chown root:root /opt/zimbra/libexec/auditswatch
chmod 0755 /opt/zimbra/libexec/auditswatch

as zimbra user

zmauditswatchctl start
zmauditswatchctl start...done

In the case that you can't receive any zmauditswatch email, and you see the next on your logs:

/opt/zimbra/data/tmp/.swatch_script.2721: cannot open pipe to : Broken pipe

Please add the sendmail in Zimbra Collaboration 8.7 using the next:

/usr/sbin/alternatives --install /usr/sbin/sendmail mta /opt/zimbra/common/sbin/sendmail 25 \
 --slave /usr/bin/mailq mta-mailq /opt/zimbra/common/sbin/mailq \
 --slave /usr/bin/newaliases mta-newaliases /opt/zimbra/common/sbin/newaliases \
--slave /usr/share/man/man1/mailq.1.gz mta-mailqman /opt/zimbra/common/share/man/man1/mailq.1 \
--slave /usr/share/man/man1/newaliases.1.gz mta-newaliasesman /opt/zimbra/common/share/man/man1/newaliases.1 \
--slave /usr/share/man/man8/sendmail.8.gz mta-sendmailman /opt/zimbra/common/share/man/man1/sendmail.1 \
--slave /usr/share/man/man5/aliases.5.gz mta-aliasesman /opt/zimbra/common/share/man/man5/aliases.5 \
--initscript zimbra

Activate it in Boot Sequence

For default zmauditswatch doesn't load at start-up, if we want to keep zmauditswatch activated also if the machine's reboot. We need to download this file Media:Zmauditswatch.tar‎ or create by ourselves:

# Init file for zmauditswatchctl
# chkconfig: 345 99 01
# description: zmauditswatchctl service
# Provides:       zmauditswatch
# Required-Start: $network $remote_fs $syslog $time nscd cron zimbra
# Required-Stop:  $network $remote_fs $syslog $time zimbra
# Default-Start:  3 5
# Default-Stop:   0 1 6
# Description:    zmauditswatchctl service

        su - zimbra -c "zmauditswatchctl $1 </dev/null"

case "$1" in
                command stop
                command start
                command start
                command stop
                command $1
                echo $"Usage: $0 {start|stop|restart|reload|status}"
exit $RETVAL

Copy the script into our init.d directory, and add it into the boot sequence:

For RHEL/CentOS 5/6 or SLES 11:

tar xvf Zmauditswatch.tar
cp zmauditswatch /etc/init.d/zmauditswatch
chmod 755 /etc/init.d/zmauditswatch
chkconfig zmauditswatch on

For Ubuntu:

tar xvf Zmauditswatch.tar
cp zmauditswatch /etc/init.d/zmauditswatch
chmod 755 /etc/init.d/zmauditswatch
sudo update-rc.d zmauditswatch defaults
sudo update-rc.d zmauditswatch enable


Web Client

We will try to attack our Zimbra Lab with one username and bad password, 10 times:


The result will be that the user can't do login anymore for 15 minutes:


The Zmauditswatchctl will send a notification to the email address that we defined before:


If we open the mail, we'll obtain more information



Sometimes we don't have a complete report of the SMTP fails, and we can be vulnerable under a brute force or Dictionary attack. With zmauditswatch enabled, we will be capable of obtain a email notification if we have an attack under SMTP.

The Zmauditswatch will send a notification to the email address that we defined before:


If we open the mail, we'll obtain more information


Log File

We can check into the log /opt/zimbra/log/zmauditswatch.out

zimbra@lab:~/bin$ tail -20 /opt/zimbra/log/zmauditswatch.out
*** auditswatch version 3.2.3 (pid:24029) started at Wed Oct  1 11:51:31 CEST 2014

IP:Acct failure threshold exceeded: X.X.X.X
IP:Acct failure threshold exceeded: X.X.X.X
Account failure threshold exceeded: X.X.X.X
IP failure threshold exceeded: X.X.X.X exceeded threshold on failure for

NOTE : Please configure with your own parameters the above script, it's an example.

Verified Against: ZCS 8.6 and 8.0 Date Created: 10/1/2014
Article ID: Date Modified: 10/4/2017

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