Fail2ban (Русский)
Fail2ban сканирует различные текстовые лог-файлы и блокирует IP, которые делают слишком много ошибок ввода пароля, обновляя правила файрвола для отклонения IP-адреса, сходно с Sshguard.
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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.
Укрепление
На данный момент fail2ban требует запуска от имени root, следовательно, вы можете дополнительно укрепить процесс с помощью systemd. Ссылка: systemd for Administrators, Part XII
Возможности
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 capabilities(7) 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.
jail.conf file being overwritten or improved during a distribution update, it is recommended to provide customizations in a jail.local file, or separate .conf files under the jail.d/ directory, e.g. jail.d/ssh-iptables.conf.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
BLACKLIST to ALL in /etc/shorewall/shorewall.conf otherwise the rule added to ban an IP address will affect only new connections.Also do not forget to add/change:
LogLevel VERBOSE
in your /etc/ssh/sshd_config. Else, password failures are not logged correctly.