Security in WordPress is taken very seriously, but as with any other system there are potential security issues that may arise if some basic security precautions aren’t taken. This article will go through some common forms of vulnerabilities, and the things you can do to help keep your WordPress installation secure.

This article is not the ultimate quick fix to your security concerns. If you have specific security concerns or doubts, you should discuss them with people whom you trust to have sufficient knowledge of computer security and WordPress.

Network Vulnerabilities

The network on both ends — the WordPress server side and the client network side — should be trusted. That means updating firewall rules on your home router and being careful about what networks you work from. An Internet cafe where you are sending passwords over an unencrypted connection, wireless or otherwise, is not a trusted network.

Your web host should be making sure that their network is not compromised by attackers, and you should do the same. Network vulnerabilities can allow passwords and other sensitive information to be intercepted.

Passwords

Many potential vulnerabilities can be avoided with good security habits. A strong password is an important aspect of this.

The goal with your password is to make it hard for other people to guess and hard for a brute force attack to succeed. Many automatic password generators are available that can be used to create secure passwords.

WordPress also features a password strength meter which is shown when changing your password in WordPress. Use this when changing your password to ensure its strength is adequate.

Things to avoid when choosing a password:

• Any permutation of your own real name, username, company name, or name of your website.
• A word from a dictionary, in any language.
• A short password.
• Any numeric-only or alphabetic-only password (a mixture of both is best).

A strong password is necessary not just to protect your blog content. A hacker who gains access to your administrator account is able to install malicious scripts that can potentially compromise your entire server.

In addition to using a strong password, it’s a good idea to enable two-step authentication as an additional security measure.

FTP

When connecting to your server you should use SFTP encryption if your web host provides it. If you are unsure if your web host provides SFTP or not, just ask them.

Using SFTP is the same as FTP, except your password and other data is encrypted as it is transmitted between your computer and your website. This means your password is never sent in the clear and cannot be intercepted by an attacker.

File Permissions

Some neat features of WordPress come from allowing various files to be writable by the web server. However, allowing write access to your files is potentially dangerous, particularly in a shared hosting environment.

It is best to lock down your file permissions as much as possible and to loosen those restrictions on the occasions that you need to allow write access, or to create specific folders with less restrictions for the purpose of doing things like uploading files.

Here is one possible permission scheme.

All files should be owned by your user account, and should be writable by you. Any file that needs write access from WordPress should be writable by the web server, if your hosting set up requires it, that may mean those files need to be group-owned by the user account used by the web server process.

/ 

The root WordPress directory: all files should be writable only by your user account, except .htaccess if you want WordPress to automatically generate rewrite rules for you.

/wp-admin/ 

The WordPress administration area: all files should be writable only by your user account.

/wp-includes/ 

The bulk of WordPress application logic: all files should be writable only by your user account.

/wp-content/ 

User-supplied content: intended to be writable by your user account and the web server process.

Within /wp-content/ you will find:

/wp-content/themes/ 

Theme files. If you want to use the built-in theme editor, all files need to be writable by the web server process. If you do not want to use the built-in theme editor, all files can be writable only by your user account.

/wp-content/plugins/ 

Plugin files: all files should be writable only by your user account.

Other directories that may be present with /wp-content/ should be documented by whichever plugin or theme requires them. Permissions may vary.

Changing file permissions

If you have shell access to your server, you can change file permissions recursively with the following command:

For Directories:

find /path/to/your/wordpress/install/ -type d -exec chmod 755 {} \;

For Files:

find /path/to/your/wordpress/install/ -type f -exec chmod 644 {} \;

Regarding Automatic Updates

When you tell WordPress to perform an automatic update, all file operations are performed as the user that owns the files, not as the web server’s user. All files are set to 0644 and all directories are set to 0755, and writable by only the user and readable by everyone else, including the web server.

Database Security

If you run multiple blogs on the same server, it is wise to consider keeping them in separate databases each managed by a different user. This is best accomplished when performing the initial WordPress installation. This is a containment strategy: if an intruder successfully cracks one WordPress installation, this makes it that much harder to alter your other blogs.

If you administer MySQL yourself, ensure that you understand your MySQL configuration and that unneeded features (such as accepting remote TCP connections) are disabled. See Secure MySQL Database Design for a nice introduction.

Restricting Database User Privileges

For normal WordPress operations, such as posting blog posts, uploading media files, posting comments, creating new WordPress users and installing WordPress plugins, the MySQL database user only needs data read and data write privileges to the MySQL database; SELECT, INSERT, UPDATE and DELETE.

Therefore any other database structure and administration privileges, such as DROP, ALTER and GRANT can be revoked. By revoking such privileges you are also improving the containment policies.

Note: Some plugins, themes and major WordPress updates might require to make database structural changes, such as add new tables or change the schema. In such case, before installing the plugin or updating a software, you will need to temporarily allow the database user the required privileges.

WARNING: Attempting updates without having these privileges can cause problems when database schema changes occur. Thus, it is NOT recommended to revoke these privileges. If you do feel the need to do this for security reasons, then please make sure that you have a solid backup plan in place first, with regular whole database backups which you have tested are valid and that can be easily restored. A failed database upgrade can usually be solved by restoring the database back to an old version, granting the proper permissions, and then letting WordPress try the database update again. Restoring the database will return it back to that old version and the WordPress administration screens will then detect the old version and allow you to run the necessary SQL commands on it. Most WordPress upgrades do not change the schema, but some do. Only major point upgrades (3.7 to 3.8, for example) will alter the schema. Minor upgrades (3.8 to 3.8.1) will generally not. Nevertheless, keep a regular backup.

Securing wp-admin

Adding server-side password protection (such as BasicAuth) to /wp-admin/ adds a second layer of protection around your blog’s admin area, the login screen, and your files. This forces an attacker or bot to attack this second layer of protection instead of your actual admin files. Many WordPress attacks are carried out autonomously by malicious software bots.

Simply securing the wp-admin/ directory might also break some WordPress functionality, such as the AJAX handler at wp-admin/admin-ajax.php. See the Resources section for more documentation on how to password protect your wp-admin/ directory properly.

The most common attacks against a WordPress blog usually fall into two categories.

1. Sending specially-crafted HTTP requests to your server with specific exploit payloads for specific vulnerabilities. These include old/outdated plugins and software.
2. Attempting to gain access to your blog by using “brute-force” password guessing.

The ultimate implementation of this “second layer” password protection is to require an HTTPS SSL encrypted connection for administration, so that all communication and sensitive data is encrypted. See Administration Over SSL.

Securing wp-includes

A second layer of protection can be added where scripts are generally not intended to be accessed by any user. One way to do that is to block those scripts using mod_rewrite in the .htaccess file. Note: to ensure the code below is not overwritten by WordPress, place it outside the # BEGIN WordPress and # END WordPress tags in the .htaccess file. WordPress can overwrite anything between these tags.

# Block the include-only files.
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^wp-admin/includes/ - [F,L]
RewriteRule !^wp-includes/ - [S=3]
RewriteRule ^wp-includes/[^/]+\.php$ - [F,L]
RewriteRule ^wp-includes/js/tinymce/langs/.+\.php - [F,L]
RewriteRule ^wp-includes/theme-compat/ - [F,L]
</IfModule>


# BEGIN WordPress

Note that this won’t work well on Multisite, as RewriteRule ^wp-includes/[^/]+\.php$ - [F,L] would prevent the ms-files.php file from generating images. Omitting that line will allow the code to work, but offers less security.

Securing wp-config.php

You can move the wp-config.php file to the directory above your WordPress install. This means for a site installed in the root of your webspace, you can store wp-config.php outside the web-root folder.

Note: Some people assert that moving wp-config.php has minimal security benefits and, if not done carefully, may actually introduce serious vulnerabilities. Others disagree.

Note that wp-config.php can be stored ONE directory level above the WordPress (where wp-includes resides) installation. Also, make sure that only you (and the web server) can read this file (it generally means a 400 or 440 permission).

If you use a server with .htaccess, you can put this in that file (at the very top) to deny access to anyone surfing for it:

<files wp-config.php>
order allow,deny
deny from all
</files>

Disable File Editing

The WordPress Dashboard by default allows administrators to edit PHP files, such as plugin and theme files. This is often the first tool an attacker will use if able to login, since it allows code execution. WordPress has a constant to disable editing from Dashboard. Placing this line in wp-config.php is equivalent to removing the ‘edit_themes’, ‘edit_plugins’ and ‘edit_files’ capabilities of all users:

define('DISALLOW_FILE_EDIT', true);

This will not prevent an attacker from uploading malicious files to your site, but might stop some attacks.

Plugins

First of all, make sure your plugins are always updated. Also, if you are not using a specific plugin, delete it from the system.

Firewall

There are many plugins and services that can act as a firewall for your website. Some of them work by modifying your .htaccess file and restricting some access at the Apache level, before it is processed by WordPress. A good example is iThemes Security or All in One WP Security. Some firewall plugins act at the WordPress level, like WordFence and try to filter attacks as WordPress is loading, but before it is fully processed.

Besides plugins, you can also install a WAF (web firewall) at your web server to filter content before it is processed by WordPress. The most popular open source WAF is ModSecurity.

A firewall can also be added between your hosting company and the Internet (security in the middle), by modifying your DNS records to pass-through the firewall. That causes all traffic to be filtered by the firewall before reaching your site. A few companies offer such service, like CloudFlare, Sucuri and Incapsula.

Plugins that need write access

If a plugin wants write access to your WordPress files and directories, please read the code to make sure it is legit or check with someone you trust. Possible places to check are the Support Forums and IRC Channel.

Code execution plugins

As we said, part of the goal of hardening WordPress is containing the damage done if there is a successful attack. Plugins which allow arbitrary PHP or other code to execute from entries in a database effectively magnify the possibility of damage in the event of a successful attack.

A way to avoid using such a plugin is to use custom page templates that call the function. Part of the security this affords is active only when you disallow file editing within WordPress.

Security through obscurity

Security through obscurity is generally an unsound primary strategy. However, there are areas in WordPress where obscuring information might help with security:

1. Rename the administrative account: When creating an administrative account, avoid easily guessed terms such as admin or webmaster as usernames because they are typically subject to attacks first. On an existing WordPress install you may rename the existing account in the MySQL command-line client with a command like UPDATE wp_users SET user_login = 'newuser' WHERE user_login = 'admin';, or by using a MySQL frontend like phpMyAdmin.
2. Change the table_prefix: Many published WordPress-specific SQL-injection attacks make the assumption that the table_prefix is wp_, the default. Changing this can block at least some SQL injection attacks.

Data Backups

Back up your data regularly, including your MySQL databases. See the main article: Backing Up Your Database.

Data integrity is critical for trusted backups. Encrypting the backup, keeping an independent record of MD5 hashes for each backup file, and/or placing backups on read-only media increases your confidence that your data has not been tampered with.

A sound backup strategy could include keeping a set of regularly-timed snapshots of your entire WordPress installation (including WordPress core files and your database) in a trusted location. Imagine a site that makes weekly snapshots. Such a strategy means that if a site is compromised on May 1st but the compromise is not detected until May 12th, the site owner will have pre-compromise backups that can help in rebuilding the site and possibly even post-compromise backups which will aid in determining how the site was compromised.

Logging

Forensics logs are your best friend when it comes to understanding your site. Contrary to popular beliefs, logs allow you to see what was done and by who and when. Unfortunately the logs will not tell you who, username, logged in, but it will allow you to identify the IP and time. Additionally, you will be able to see any of these attacks via the logs – Cross Site Scripting (XSS), Remote File Inclusion (RFI), Local File Inclusion (LFI) and Directory Traversal attempts. You will also be able to see brute force attempts.

If you get more comfortable with your logs you’ll be able to see things like, when the theme and plugin editors are being used, when someone updates your widgets and when posts and pages are added. All key elements when doing forensic work on your web server.

There are two key open-source solutions you’ll want on your web server from a security perspective, this is a layered approach to security.

OSSEC can run on any NIX distribution and will also run on Windows. When configured correctly its very powerful. The idea is correlate and aggregate all the logs. You have to be sure to configure it to capture all access_logs and error_logs and if you have multiple websites on the server account for that. You’ll also want to be sure to filter out the noise. By default you’ll see a lot of noise and you’ll want to configure it to be really effective.

Monitoring

Sometimes prevention is not enough and you may still be hacked. That’s why intrusion detection/monitoring is very important. It will allow you to react faster, find out what happened and recover your site.

Monitoring your logs

If you are on a dedicated or virtual private server, in which you have the luxury of root access, you have the ability easily configure things so that you can see what’s going on. OSSEC easily facilitates this and here is a little write up that might help you out OSSEC for Website Security – Part I.

Monitoring your files for changes

When an attack happens, it always leave traces. Either on the logs or on the file system (new files, modified files, etc). If you are using OSSEC for example, it will monitor your files and alert you when they change.

Goals

The goals of file system tracking include:

• Monitor changed and added files
• Log changes and additions
• Ability to revert granular changes
• Automated alerts

General approaches

Administrators can monitor file system via general technologies such as:

• System utilities
• Revision control
• OS/kernel level monitoring

Specific tools

Options for file system monitoring include:

• diff – build clean test copy of your site and compare against production
• Git – source code management
• inotify and incron – OS kernel level file monitoring service that can run commands on filesystem events
• Watcher – Python inotify library
• OSSEC – Open Source Host-based Intrusion Detection System that performs log analysis, file integrity checking, policy monitoring, rootkit detection, real-time alerting and active response.

Considerations

When configuring a file based monitoring strategy, there are many considerations, including the following.

Run the monitoring script/service as root

This would make it hard for attackers to disable or modify your file system monitoring solution.

Disable monitoring during scheduled maintenance/upgrades

This would prevent unnecessary notifications when you are performing regular maintenance on the site.

Monitor only executable filetypes

It may be reasonably safe to monitor only executable file types, such as .php files, etc.. Filtering out non-executable files may reduce unnecessary log entries and alerts.

Use strict file system permissions

Read about securing file permissions and ownership. In general, avoid allowing execute and write permissions to the extent possible.

Monitoring your web server externally

If the attacker tries to deface your site or add malware, you can also detect these changes by using a web-based integrity monitor solution. This comes in many forms today, use your favorite search engine and look for Web Malware Detection and Remediation and you’ll likely get a long list of service providers.