Tested on Centos 7. Deployent: Keycloak with an Nginx proxy_pass
Add regular-expression filter under /etc/fail2ban/filter.d/keycloak.conf:
[INCLUDES]
before = common.conf
[Definition]
_threadName = [a-z][-_0-9a-z]*(\s[a-z][-_0-9a-z]*)*
_userId = (null|[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12})
_realmName = ([a-zA-Z][-_a-zA-Z0-9]*)
failregex =
^.*WARN\s+\[org\.keycloak\.events\]\s+\(%(_threadName)s\) type=LOGIN_ERROR, realmId=%(_realmName)s, clientId=security-admin-console, userId=%(_userId)s, ipAddress=<HOST>
ignoreregex =
Configure a new jail to get keycloak log messages directly from systemd, it will block http (80) and https (443) for the ofending IP. Create the file /etc/fail2ban/jail.d/keycloak.conf:
[keycloak]
enabled = true
filter = keycloak
maxretry = 2
findtime = 10
bantime = 10
action = iptables-multiport[name=NoAuthFailures, port="http,https"]
backend = systemd
journalmatch = _SYSTEMD_UNIT=keycloak.service
Simulate some failed logins and test your regular expressions:
sudo fail2ban-regex -v /opt/keycloak/standalone/log/server.log /etc/fail2ban/filter.d/keycloak.conf
Restart fail2ban for jail to be enabled:
sudo systemctl restart fail2ban.service
During normal operation of fail2ban, we can check the status of a particular jail:
sudo fail2ban-client status keycloak
@danifr Thank you for the write-up, but I suppose there is a typo in the filter file's path - it should be
/etc/fail2ban/filter.d/keycloak.conf