nix/nixos/common/modules/fail2ban/traefik.nix

{ pkgs, ... }: {

  # References: 
  # https://blog.lrvt.de/configuring-fail2ban-with-traefik/
  # https://nixos.wiki/wiki/Fail2ban#Extending_Fail2ban

  services.logrotate = {
    enable = true;
    checkConfig = true;
    settings = {
      "/var/log/traefik/access.log" = {
        frequency = "daily";
        rotate = 30;
      };
    };
  };

  services.fail2ban.jails = {
    traefik-general-forceful-browsing = {
      settings = {
        enabled = true;
        filter = "traefik-general-forceful-browsing";
        action = "action-ban-docker-forceful-browsing";
        logpath = "/var/log/traefik/access.log";
        backend = "auto";
        findtime = 600;
        bantime = 600;
        maxretry = 5;
      };
    };
  };

  environment.etc= {
    "fail2ban/filter.d/traefik-general-forceful-browsing.conf".text = pkgs.lib.mkDefault (pkgs.lib.mkAfter ''
      [INCLUDES]

      [Definition]

      # fail regex based on traefik JSON access logs with enabled user agent logging
      failregex = ^{"ClientAddr":"<F-CLIENTADDR>.*</F-CLIENTADDR>","ClientHost":"<HOST>","ClientPort":"<F-CLIENTPORT>.*</F-CLIENTPORT>","ClientUsername":"<F-CLIENTUSERNAME>.*</F-CLIENTUSERNAME>","DownstreamContentSize":<F-DOWNSTREAMCONTENTSIZE>.*</F-DOWNSTREAMCONTENTSIZE>,"DownstreamStatus":<F-DOWNSTREAMSTATUS>.*</F-DOWNSTREAMSTATUS>,"Duration":<F-DURATION>.*</F-DURATION>,"OriginContentSize":<F-ORIGINCONTENTSIZE>.*</F-ORIGINCONTENTSIZE>,"OriginDuration":<F-ORIGINDURATION>.*</F-ORIGINDURATION>,"OriginStatus":(405|404|403|402|401),"Overhead":<F-OVERHEAD>.*</F-OVERHEAD>,"RequestAddr":"<F-REQUESTADDR>.*</F-REQUESTADDR>","RequestContentSize":<F-REQUESTCONTENTSIZE>.*</F-REQUESTCONTENTSIZE>,"RequestCount":<F-REQUESTCOUNT>.*</F-REQUESTCOUNT>,"RequestHost":"<F-CONTAINER>.*</F-CONTAINER>","RequestMethod":"<F-REQUESTMETHOD>.*</F-REQUESTMETHOD>","RequestPath":"<F-REQUESTPATH>.*</F-REQUESTPATH>","RequestPort":"<F-REQUESTPORT>.*</F-REQUESTPORT>","RequestProtocol":"<F-REQUESTPROTOCOL>.*</F-REQUESTPROTOCOL>","RequestScheme":"<F-REQUESTSCHEME>.*</F-REQUESTSCHEME>","RetryAttempts":<F-RETRYATTEMPTS>.*</F-RETRYATTEMPTS>,.*"StartLocal":"<F-STARTLOCAL>.*</F-STARTLOCAL>","StartUTC":"<F-STARTUTC>.*</F-STARTUTC>","TLSCipher":"<F-TLSCIPHER>.*</F-TLSCIPHER>","TLSVersion":"<F-TLSVERSION>.*</F-TLSVERSION>","entryPointName":"<F-ENTRYPOINTNAME>.*</F-ENTRYPOINTNAME>","level":"<F-LEVEL>.*</F-LEVEL>","msg":"<F-MSG>.*</F-MSG>",("request_User-Agent":"<F-USERAGENT>.*</F-USERAGENT>",){0,1}?"time":"<F-TIME>.*</F-TIME>"}$

      # custom date pattern for traefik JSON access logs
      # based on https://github.com/fail2ban/fail2ban/issues/2558#issuecomment-546738270
      datepattern = "StartLocal"\s*:\s*"%%Y-%%m-%%d[T]%%H:%%M:%%S\.%%f\d*(%%z)?",

      # ignore common errors like missing media files or JS/CSS/TXT/ICO stuff
      ignoreregex = ^{"ClientAddr":"<F-CLIENTADDR>.*</F-CLIENTADDR>","ClientHost":"<HOST>","ClientPort":"<F-CLIENTPORT>.*</F-CLIENTPORT>","ClientUsername":"<F-CLIENTUSERNAME>.*</F-CLIENTUSERNAME>","DownstreamContentSize":<F-DOWNSTREAMCONTENTSIZE>.*</F-DOWNSTREAMCONTENTSIZE>,"DownstreamStatus":<F-DOWNSTREAMSTATUS>.*</F-DOWNSTREAMSTATUS>,"Duration":<F-DURATION>.*</F-DURATION>,"OriginContentSize":<F-ORIGINCONTENTSIZE>.*</F-ORIGINCONTENTSIZE>,"OriginDuration":<F-ORIGINDURATION>.*</F-ORIGINDURATION>,"OriginStatus":(405|404|403|402|401),"Overhead":<F-OVERHEAD>.*</F-OVERHEAD>,"RequestAddr":"<F-REQUESTADDR>.*</F-REQUESTADDR>","RequestContentSize":<F-REQUESTCONTENTSIZE>.*</F-REQUESTCONTENTSIZE>,"RequestCount":<F-REQUESTCOUNT>.*</F-REQUESTCOUNT>,"RequestHost":"<F-REQUESTHOST>.*</F-REQUESTHOST>","RequestMethod":"<F-REQUESTMETHOD>.*</F-REQUESTMETHOD>","RequestPath":"<F-REQUESTPATH>.*(\.png|\.txt|\.jpg|\.ico|\.js|\.css|\.ttf|\.woff|\.woff2)(/)*?</F-REQUESTPATH>","RequestPort":"<F-REQUESTPORT>.*</F-REQUESTPORT>","RequestProtocol":"<F-REQUESTPROTOCOL>.*</F-REQUESTPROTOCOL>","RequestScheme":"<F-REQUESTSCHEME>.*</F-REQUESTSCHEME>","RetryAttempts":<F-RETRYATTEMPTS>.*</F-RETRYATTEMPTS>,.*"StartLocal":"<F-STARTLOCAL>.*</F-STARTLOCAL>","StartUTC":"<F-STARTUTC>.*</F-STARTUTC>","TLSCipher":"<F-TLSCIPHER>.*</F-TLSCIPHER>","TLSVersion":"<F-TLSVERSION>.*</F-TLSVERSION>","entryPointName":"<F-ENTRYPOINTNAME>.*</F-ENTRYPOINTNAME>","level":"<F-LEVEL>.*</F-LEVEL>","msg":"<F-MSG>.*</F-MSG>",("request_User-Agent":"<F-USERAGENT>.*</F-USERAGENT>",){0,1}?"time":"<F-TIME>.*</F-TIME>"}$
    '');

    "fail2ban/action.d/action-ban-docker-forceful-browsing.conf".text = pkgs.lib.mkDefault (pkgs.lib.mkAfter ''
      [Definition]

      actionban = ${pkgs.iptables}/bin/iptables -I DOCKER-USER -m string --algo bm --string 'X-Forwarded-For: <ip>' -j DROP
                  ${pkgs.iptables}/bin/iptables -A INPUT -s <ip> -j DROP

      actionunban = ${pkgs.iptables}/bin/iptables -D DOCKER-USER -m string --algo bm --string 'X-Forwarded-For: <ip>' -j DROP
                    ${pkgs.iptables}/bin/iptables -D INPUT -s <ip> -j DROP
    '');
  };
}