Fail2ban (Русский)
Fail2ban scans various textual log files and bans IP that makes too many password failures by updating firewall rules to reject the IP address, similar to Sshguard.
Contents
Установка
Установите fail2ban из официальных репозиториев.
Если вы хотите, чтобы Fail2ban отсылал письма, когда кто-то был забанен, вы должны настроить SSMTP (к примеру).
systemd
Используйте юнит сервис fail2ban.service, в соответствии с инструкциями systemd.
Hardening
Currently, fail2ban requires to run as root, therefore you may wish to consider some additional hardening on the process with systemd. Ref:systemd for Administrators, Part XII
Capabilities
For added security consider limiting fail2ban capabilities by specifying CapabilityBoundingSet in the drop-in configuration file for the provided fail2ban.service:
/etc/systemd/system/fail2ban.service.d/capabilities.conf
[Service] CapabilityBoundingSet=CAP_DAC_READ_SEARCH CAP_NET_ADMIN CAP_NET_RAW
In the example above, CAP_DAC_READ_SEARCH will allow fail2ban full read access, and CAP_NET_ADMIN and CAP_NET_RAW allow setting of firewall rules with iptables. Additional capabilities may be required, depending on your fail2ban configuration. See man capabilities for more info.
Filesystem Access
Also considering limiting file system read and write access, by using ReadOnlyDirectories and ReadWriteDirectories, again under the [Service] section. For example:
ReadOnlyDirectories=/ ReadWriteDirectories=/var/run/fail2ban /var/lib/fail2ban /var/spool/postfix/maildrop /tmp
In the example above, this limits the file system to read-only, except for /var/run/fail2ban for pid and socket files, and /var/spool/postfix/maildrop for postfix sendmail. Again, this will be dependent on you system configuration and fail2ban configuration. The /tmp directory is needed for some fail2ban actions. Note that adding /var/log is necessary if you want fail2ban to log its activity.
SSH jail
Edit /etc/fail2ban/jail.conf and modify the ssh-iptables section to enable it and configure the action.
If your firewall is iptables:
[ssh-iptables]
enabled = true
filter = sshd
action = iptables[name=SSH, port=ssh, protocol=tcp]
sendmail-whois[name=SSH, dest=your@mail.org, sender=fail2ban@mail.com]
logpath = /var/log/auth.log
maxretry = 5
Fail2Ban from version 0.9 can also read directly from the systemd journal by setting backend = systemd.
If your firewall is shorewall:
[ssh-shorewall]
enabled = true
filter = sshd
action = shorewall
sendmail-whois[name=SSH, dest=your@mail.org, sender=fail2ban@mail.com]
logpath = /var/log/auth.log
maxretry = 5
Also do not forget to add/change:
LogLevel VERBOSE
in your /etc/ssh/sshd_config. Else, password failures are not logged correctly.