fail2ban

Daemon to ban hosts that cause multiple authentication errors

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README FOR SOLARIS INSTALLATIONS

By Roy Sigurd Karlsbakk [email protected]

ABOUT

This README is meant for those wanting to install fail2ban on Solaris 10,
OpenSolaris, OpenIndiana etc. To some degree it may as well be useful for
users of older Solaris versions and Nexenta, but don’t rely on it.

READ ME FIRST

If I use the term Solaris, I am talking about any Solaris dialect, that is, the
official Sun/Oracle ones or derivatives. If I describe an OS as
“OpenSolaris-based”, it means it’s either OpenSolaris, OpenIndiana or one of the
other, but /not/ the Nexenta family, since this only uses the OpenSolaris/
IllumOS kernel and not the userland. If I say Solaris 10, I mean Solaris 10 and
perhaps, if you’re lucky and have some good gods on your side, it may also apply
to Solaris 9 or even 8 and hopefully in the new Solaris 11 whenever that may be
released. Quoted lines of code, settings etc. are indented with two spaces.
This does not mean you should use that indentation, especially in config files
where they can be harmful. Optional settings are prefixed with OPT: while
required settings are prefixed with REQ:. If no prefix is found, regard it as a
required setting.

INSTALLATION ON SOLARIS

The installation is straight forward on Solaris as well as on linux/bsd/etc.
./setup.py install installs the general packages in /usr/bin on OpenSolaris-
based distros or (at least on this box) under /usr/sfw/bin on Solaris 10. In
the files/ directory you will find the file solaris-fail2ban.xml containing the
Solaris service. To install this, run the following command as root (or with
sudo):

svccfg import files/solaris-fail2ban.xml

This should normally without giving an error. If you get an error, deal with it,
and please post any relevant info (or fixes?) to the fail2ban mailing list.
Next install the service handler - copy the script in and allow it to be executed:

cp files/solaris-svc-fail2ban /lib/svc/method/svc-fail2ban
chmod +x /lib/svc/method/svc-fail2ban

CONFIGURE SYSLOG

For some reason, a default Solaris installation does not log ssh login attempts,
and since fail2ban works by monitoring logs, enabling this logging is rather
important for it to work. To enable this, edit /etc/syslog.conf and add a line
at the end:

auth.info /var/adm/auth.log

Save the file and exit, and run

touch /var/adm/auth.log

The Solaris system logger will not create a non-existing file. Now, restart
the system logger.

svcadm restart system-log

Try to ssh into localhost with ssh asdf@localhost and enter an invalid password.
Make sure this is logged in the above file. When done, you may configure
fail2ban.

FAIL2BAN CONFIGURATION

OPT: Create /etc/fail2ban/fail2ban.local containing:

Fail2Ban configuration file for logging fail2ban on Solaris

[Definition]

logtarget = /var/adm/fail2ban.log

REQ: Create /etc/fail2ban/jail.local containing:

[ssh-tcpwrapper]

enabled = true
filter = sshd
action = hostsdeny[daemon_list=sshd]
sendmail-whois[name=SSH, [email protected]]
ignoreregex = for myuser from
logpath = /var/adm/auth.log

Set the sendmail dest address to something useful or drop the line to stop it spamming you.
Set ‘myuser’ to your username to avoid banning yourself or remove the line.

START (OR RESTART) FAIL2BAN

Enable the fail2ban service with

svcadm enable fail2ban

When done, check that all services are running well

svcs -xv

GOTCHAS AND FIXMES

  • It seems the installation may be starting fail2ban automatically. If this is
    done, fail2ban will not start, but no errors will be returned from svcs
    (above). Check if it’s running with ‘ps -ef | grep fail2ban’ and manually kill
    the PID if it is. Re-enable fail2ban and try again

    svcadm disable fail2ban
    svcadm enable fail2ban

  • If svcs -xv says that fail2ban failed to start or svcs says it’s in maintenance mode
    check /var/svc/log/network-fail2ban:default.log for clues.
    Check permissions on /var/adm, /var/adm/auth.log /var/adm/fail2ban.log and /var/run/fail2ban
    You may need to:

    sudo mkdir /var/run/fail2ban

  • Fail2ban adds lines like these to /etc/hosts.deny:

    sshd: 1.2.3.4