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03/06/2019

Nginx: Block URL Access (wp-admin/wp-login.php) To All Except One IP Address



I am the small business owner and runs my own web-site. I have noticed increased cracking activity against by blog. What’s the best way to block WordPress URLs such as example.com/blog/wp-login.php and example.com/blog/wp-admin/ in the nginx web-server?

Attacks on WordPress based sites are not new. However, recently many news outlets reported that there’s a fairly large brute force attack happening on WordPress users on multiple hosts. The attacker is brute force attacking the WordPress administrative portals (example.com/wp-admin/), using the username “admin” and trying thousands of passwords.

Nginx block access WordPress administrative portals

Edit the file nginx.conf, enter:
# vi /etc/nginx/nginx.conf
Append the following all and deny all nginx config directives in server context:

  location ~ ^/(wp-admin|wp-login.php) {
                allow 1.2.3.4;
                deny all;
  }

If your blog located in /blog/ sub-directory, try:

  location ~ ^/blog/(wp-admin|wp-login.php) {
                allow 1.2.3.4;
                deny all;
  }

Replace 1.2.3.4 with your actual static IP address. Here is a sample config file

upstream apachebackend  {
 server 192.168.1.10:8080 weight=6;
 server 192.168.1.11:8080 weight=5; 
 server 192.168.1.12:8080 weight=5; 
 server 192.168.1.13:8080 weight=5; 
 #server 127.0.0.1:8080 weight=1; 
}
 
server {
      access_log  /var/log/nginx/access.log;
      error_log   /var/log/nginx/error.log;
      index       index.html;
      listen      75.126.153.206:80 default;
      root        /usr/share/nginx/html;
      server_name sxi.io sxi.io;
 
  ## PROXY - Web
      location / {
        proxy_pass  http://apachebackend;
        proxy_next_upstream error timeout invalid_header http_500 http_502 http_503;
        proxy_redirect off;
        proxy_buffering off;
 
        proxy_set_header        Host            $host;
        proxy_set_header        X-Real-IP       $remote_addr;
        proxy_set_header        X-Forwarded-For $proxy_add_x_forwarded_for;
      }
      location ~ ^/(wp-admin|wp-login.php) {
           allow 1.2.3.4;
           deny all;
           proxy_pass  http://apachebackend;
           proxy_next_upstream error timeout invalid_header http_500 http_502 http_503;
           proxy_set_header        Host            $host;
           proxy_set_header        X-Real-IP       $remote_addr;
           proxy_set_header        X-Forwarded-For $proxy_add_x_forwarded_for;
      }
}

Restart / reload the nginx web-server, enter:
# /etc/init.d/nginx reload

Test it

Visit your blog url such as http://sxi.io/cms/wp-login.php or http://bash.sxi.io/wp-admin/
Sample outputs:

Fig.01: Nginx blocking WordPress Admin Portal

How do I customize 403 error page?

See create a custom static HTTP 404 or HTTP 403 error page for more information.

Other recommendations

First, set SSL certificate on nginx. Edit the file wp-config.php and append the following directive:

define('FORCE_SSL_ADMIN', true);

Save and close the file. The FORCE_SSL_ADMIN option force WordPress to secure logins and the admin area so that both passwords and cookies are never sent in the clean over http. Use the curl command to see http headers, enter:
$ curl -I http://sxi.io/cms/wp-admin/

HTTP/1.1 302 Found
Server: nginx
Date: Sun, 14 Apr 2013 09:01:44 GMT
Content-Type: text/html
Connection: keep-alive
Keep-Alive: timeout=60
Vary: Cookie
Expires: Wed, 11 Jan 1984 05:00:00 GMT
Cache-Control: no-cache, must-revalidate, max-age=0
Pragma: no-cache
Location: https://sxi.io/cms/wp-admin/

I also suggest that you add the following firewall rules so that SSL part is only accessible to you:

## Open port 443 to you only ##
## Allow your home/office static IP 1.2.3.4 at port 443
/sbin/iptables -A INPUT -s 1.2.3.4  -m state --state NEW -p tcp --dport 443 --destination YOUR-Web-Server-SSL-IP-HERE -j ACCEPT
 
## Make sure  you DROP the rest of the world for 75.126.153.203 for TCP port 443 ###
##/sbin/iptables -A INPUT -s 0/0  -m state --state NEW -p tcp --dport 443 --destination YOUR-Web-Server-SSL-IP-HERE -j DROP
See also

Posted by: SXI ADMIN

The author is the creator of nixCraft and a seasoned sysadmin, DevOps engineer, and a trainer for the Linux operating system/Unix shell scripting. Get the latest tutorials on SysAdmin, Linux/Unix and open source topics via RSS/XML feed or weekly email newsletter.

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