Difference between revisions of "Fail2Ban"
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Fail2Ban is rather simple. I have a home server connected to | Fail2Ban is rather simple. I have a home server connected to | ||
− | the Internet which runs apache, samba, sshd, | + | the Internet which runs apache, samba, sshd, and some other |
− | + | services. I saw in my logs that people are trying to log into | |
− | + | my box using brute force, either "manually" or with scripts. | |
− | + | They have tried 10, 20 and sometimes more user/password | |
− | + | combinations, without success. In order to discourage these | |
− | + | script kiddies, I wanted sshd to refuse login from a specific | |
− | + | IP address after 3 password failures. After some Google | |
− | + | searches, I found that sshd was not able of that, so I | |
− | nothing :-( So I | + | searched for a script or program that does it. I found |
+ | nothing. :-( So I decided to write my own, and to learn | ||
+ | Python. :-) | ||
For each section defined in the configuration file, Fail2Ban | For each section defined in the configuration file, Fail2Ban | ||
tries to find lines which match the failregex. Then it | tries to find lines which match the failregex. Then it | ||
retrieves the message time using timeregex and timepattern. | retrieves the message time using timeregex and timepattern. | ||
− | It finally gets the | + | It finally gets the IP, and if that IP has already caused 3 |
− | + | or more password failures within the last banTime, it is | |
− | + | banned for banTime using a firewall rule. This rule is set | |
− | + | by the user in the configuration file; thus, Fail2Ban can be | |
− | + | adapted for many different firewalls. After banTime, the rule | |
− | + | is deleted. Notice that if no "plain" IP is available, | |
− | + | Fail2Ban tries to do a DNS lookup in order to find one or | |
+ | several IP addresses to ban. | ||
− | Sections can be freely added so it is possible to monitor | + | Sections can be freely added to the configuration file, so it |
− | + | is possible to monitor several daemons at the same time. | |
− | + | Fail2Ban runs on my server and does its job rather well :-) | |
− | + | The idea is to make Fail2Ban usable with daemons and services | |
− | require a login (sshd, telnetd, ...) and with different | + | that require a login (sshd, telnetd, ...) and with different |
firewalls. | firewalls. | ||
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------------- | ------------- | ||
− | + | Requires: python-2.4 (http://www.python.org) | |
− | To install, just | + | To install, just run: |
> tar xvfj fail2ban-0.6.1.tar.bz2 | > tar xvfj fail2ban-0.6.1.tar.bz2 | ||
Line 70: | Line 73: | ||
RedHat: packages are available on the website. | RedHat: packages are available on the website. | ||
− | Fail2Ban should now be correctly installed. Just | + | Fail2Ban should now be correctly installed. Just run: |
> fail2ban -h | > fail2ban -h |
Revision as of 01:28, 20 August 2006
__ _ _ ___ _ / _|__ _(_) |_ ) |__ __ _ _ _ | _/ _` | | |/ /| '_ \/ _` | ' \ |_| \__,_|_|_/___|_.__/\__,_|_||_| ============================================================= Fail2Ban (version 0.6.1) 2006/03/16 ============================================================= Fail2Ban scans log files like /var/log/pwdfail and bans IP that makes too many password failures. It updates firewall rules to reject the IP address. These rules can be defined by the user. Fail2Ban can read multiple log files such as sshd or Apache web server ones. This is my first Python program. Moreover, English is not my mother tongue... More details: ------------- Fail2Ban is rather simple. I have a home server connected to the Internet which runs apache, samba, sshd, and some other services. I saw in my logs that people are trying to log into my box using brute force, either "manually" or with scripts. They have tried 10, 20 and sometimes more user/password combinations, without success. In order to discourage these script kiddies, I wanted sshd to refuse login from a specific IP address after 3 password failures. After some Google searches, I found that sshd was not able of that, so I searched for a script or program that does it. I found nothing. :-( So I decided to write my own, and to learn Python. :-) For each section defined in the configuration file, Fail2Ban tries to find lines which match the failregex. Then it retrieves the message time using timeregex and timepattern. It finally gets the IP, and if that IP has already caused 3 or more password failures within the last banTime, it is banned for banTime using a firewall rule. This rule is set by the user in the configuration file; thus, Fail2Ban can be adapted for many different firewalls. After banTime, the rule is deleted. Notice that if no "plain" IP is available, Fail2Ban tries to do a DNS lookup in order to find one or several IP addresses to ban. Sections can be freely added to the configuration file, so it is possible to monitor several daemons at the same time. Fail2Ban runs on my server and does its job rather well :-) The idea is to make Fail2Ban usable with daemons and services that require a login (sshd, telnetd, ...) and with different firewalls. Installation: ------------- Requires: python-2.4 (http://www.python.org) To install, just run: > tar xvfj fail2ban-0.6.1.tar.bz2 > cd fail2ban-0.6.1 > python setup.py install This will install Fail2Ban into /usr/lib/fail2ban. The fail2ban executable is placed into /usr/bin. Gentoo: ebuilds are available on the website. Debian: Fail2Ban is in Debian unstable. RedHat: packages are available on the website. Fail2Ban should now be correctly installed. Just run: > fail2ban -h to see if everything is alright. You can configure fail2ban with a config file. Different kind of configuration files are available: iptables: copy config/fail2ban.conf.iptables to /etc/fail2ban.conf hosts.deny: copy config/fail2ban.conf.hostsdeny to /etc/fail2ban.conf shorewall: copy config/fail2ban.conf.shorewall to /etc/fail2ban.conf Do not forget to edit fail2ban.conf to meet your needs. You can use the initd script available in config/. Copy <dist>-initd to /etc/init.d/fail2ban. Gentoo users must copy gentoo-confd to /etc/conf.d/fail2ban. You can start fail2ban: > /etc/init.d/fail2ban start Gentoo users can add it to the default runlevel: > rc-update add fail2ban default Configuration: -------------- You can configure fail2ban using the file /etc/fail2ban.conf or using command line options. Command line options override the value stored in fail2ban.conf. Here are the command line options: -b start in background -c <FILE> read configuration file FILE -p <FILE> create PID lock in FILE -h display this help message -i <IP(s)> IP(s) to ignore -k kill a currently running instance -r <VALUE> allow a max of VALUE password failure [maxfailures] -t