Top 5 Security Loopholes in WordPress Installations (And How to Plug Them)


As a web developer and cybersecurity analyst, I often get asked about WordPress security by clients and colleagues.

There‘s a perception that WordPress is inherently insecure and risky to use for important sites. While no software is 100% secure, these concerns are often overblown or based on outdated information.

The truth is that with proper precautions, WordPress can absolutely be hardened to meet stringent security requirements. After examining numerous reports, advisories and real-world incidents, I‘ve identified the top 5 security loopholes plaguing WordPress sites.

In this comprehensive guide, I‘ll walk through each loophole in depth, with straight-forward, actionable steps on how to plug them. My goal is to equip you with the knowledge to secure any WordPress site and shut down the most common attack vectors.

So let‘s dive in and explore the top 5 security loopholes in WordPress, as well as fixes and best practices to address them. I‘ve got your back!

1. Weak User Passwords

Let‘s kick things off with user account security, starting with weak passwords.

In my experience doing penetration testing and forensic analysis, poor password practices are the most common issue compromising WordPress sites.

It simply takes one guessable password to give an attacker full control and admin access. From there, anything is possible, from subtle data exfiltration to a complete site takeover or destruction.

WordPress admins tend to fall into some bad password habits:

• Using simple, easy-to-guess passwords based on the site name, business name, "password", etc.
• Re-using the same password across multiple sites.
• Never changing default passwords or forcing password resets.
• Not using a password manager.
• No multi-factor authentication.

These mistakes can lead to a breach. Based on my findings, here are 5 tips to strengthen your WordPress user passwords:

Use Strong Passwords

The #1 rule is passwords must be complex and cryptographically strong:

• At least 12 characters (20+ ideal)
• Truly random – no words or phrases
• Mix of all characters – uppercase, lowercase, numbers, symbols
• Generated by a password manager like LastPass

Weak passwords get cracked in seconds. Strong ones take centuries.

Unique Password Per Site

Never reuse the same password on different sites. A breach on one site puts all your accounts at risk.

Use your password manager to generate a long, random unique password for each site and user.

Change Defaults

Admin accounts are prime targets. Change the default "admin" username and create an extremely strong password of 32+ characters for it.

For any default accounts, reset the passwords to new strong, unique ones. Don‘t leave any doors unlocked!

Limit Login Attempts

Brute force attacks that try millions of password guesses are a threat. Limit login attempts to 5-10 tries, after which the account gets locked out. This frustrates password cracking.

Plugins like Loginizer can implement login attempt limits and lockouts automatically.

Enable Two-Factor Authentication (2FA)

2FA adds another layer of protection by requiring your password plus a code generated by an authenticator app or sent via SMS.

Popular 2FA plugins include Google Authenticator, Authy, and Duo Security. Enable 2FA for all admin and Editor/Author accounts.

If you follow these password best practices diligently, it becomes orders of magnitude harder for an attacker to gain that initial foothold through a weak or guessed password.

Well done – you‘ve closed one of the most exploited WordPress security holes!

2. Outdated Software

Once users are locked down, another common attack vector is exploiting known vulnerabilities in outdated software.

WordPress and its plugins/themes are updated frequently with security and feature improvements. Running outdated versions leaves holes open that can be leveraged by attackers.

In one incident I investigated, the site owners dismissed update nag notices for 4+ years. The site got hacked using an exploit patched years ago in newer versions. Outdated software effectively disables your existing security controls.

Here are some tips to keep your software patched and secure:

Update WordPress Core

Keep your WordPress core install updated to the latest stable version. Enabling automatic background updates is recommended for convenience and getting fixes quickly.

Monitor WordPress security advisories for newly discovered vulnerabilities and exploits that require urgent upgrade.

Update Plugins & Themes

Plugins and themes add a lot of functionality, but also vulnerabilities. The most common infection vectors I see are compromised plugins and themes.

Aggressively update them to stay on top of security fixes. Avoid abandonware that is never updated. Favor reputable maintained software.

Update Supporting Software

It‘s not just WordPress core – everything in your environment impacts security:

• PHP – Run current stable version supported by WordPress. Avoid old, insecure versions.
• Web Server – Keep web server software like Apache and Nginx patched.
• Database – MySQL/MariaDB updates eliminate database exploitation.
• Operating System – Hardened Linux like Ubuntu/CentOS with latest security updates.

Backups

Before updating, always have recent backups stored securely offline. This gives you insurance in case an update causes problems.

Backups also enable easy recovery from any security incidents by restoring a clean version. Test backups regularly!

Updating religiously eliminates a major attack surface. It does require diligence and maintenance, but is one of the most effective WordPress security measures you can take. Don‘t get caught with your software down!

3. Default Database Table Prefix

Moving deeper in the stack, the next security hole relates to the WordPress database structure itself.

When WordPress is installed, it creates database tables with the default prefix wp_ – for example wp_posts, wp_comments, wp_users and so on.

This default table prefix is well known and makes the database structure predictable. If an attacker gains access to the database through an exploit, they immediately know the names of all the core WordPress tables.

With minimal effort, the attacker can:

• Quickly locate tables like wp_users containing credentials.
• Identify where sensitive data like posts and comments are stored.
• Craft malicious queries with the right table names and columns.
• Drop tables and delete data if permissions allow it.

Many attacks I‘ve analyzed relied on the attacker‘s knowledge of the default WordPress table structure and names. It streamlined the attack and made the hacker‘s job trivial.

Thankfully this is easy to thwart:

During installation, choose a random, non-default table prefix like xyz_ or let the installer generate a secure one for you.

This applies the new prefix to all table names. For example wp_users becomes xyz_users.

Now the database structure is obscured and non-obvious to attackers. They lose the advantage of predictable table names and must put in more guesswork.

This simple step of forgoing the default table prefix closes an important vulnerability that enables potential exploits. It‘s a no-brainer best practice for hardening WordPress.

4. Weak Server User Passwords

Up to this point, we‘ve focused on vulnerabilities within WordPress itself. But it‘s critical to lock down the underlying server environment too.

Web servers like Apache and Nginx run worker processes under operating system accounts typically called www-data, apache, nginx or www.

If an attacker gains server shell access through an exploit, they will target these accounts next. Weak credentials makes the attacker‘s job trivial.

With access to the web server user, attackers can:

• Modify server config files to open up security holes. For example, disabling .htaccess protections.
• Access raw HTTP request data not filtered by WordPress.
• Leverage elevated OS privileges to read sensitive files like WordPress wp-config.php.
• Modify or delete webroot files and database data.

To prevent this dangerous scenario:

• Use very strong 32+ character randomized passwords for server user accounts.
• Restrict accounts only to minimum OS access needed for web server operation.
• Disable root login and use sudo where privileged commands are absolutely required.
• Limit access to files like wp-config.php that contain credentials and keys.

A good practice is assigning separate server user accounts for each site/app. For example:

user: site1_web
user: site2_web
user: site3_web 

This contains the blast radius if one account is compromised, by not granting backend access to all sites.

Hardening your server accounts denies attackers the keys to your kingdom. It adds essential redundancy past application security.

And if you‘re using a managed hosting provider, make sure you inquiry about how they secure underlying server accounts as well! This should be a standard question when vetting hosts.

5. Not Using HTTPS

Last but certainly not least, we have HTTPS and SSL/TLS encryption.

Deploying transport layer encryption needs to be mandatory for all WordPress sites, without exception. An unencrypted HTTP site is hugely risky in 2022.

Based on my experience, here are some of the main benefits of utilizing HTTPS:

• Encrypted traffic prevents man-in-the-middle attacks that intercept unencrypted requests and responses.
• Hides sensitive data submitted in forms like passwords, contact forms, and any POST data.
• Enables HTTP Strict Transport Security (HSTS) to force encryption and prevent downgrade attacks.
• Required for powerful web security features like secure cookies and Certificate Transparency (CT).
• Adds assurance it‘s an authentic site and boosts visitor trust. SEO and browser trust rankings benefit as well.

Without encryption, I‘ve seen everything from credentials to financial information to private customer data snatched out of the air via packet sniffing. It‘s like broadcasting your site in plain text publicly.

Thankfully getting and installing SSL certificates is quick, easy and often free these days via services like Let‘s Encrypt. There‘s truly no good reason for not utilizing HTTPS.

To properly implement HTTPS:

• Get an SSL certificate from your host or a certificate authority like Let‘s Encrypt.
• Install the certificate on your server and configure your site to use HTTPS endpoints.
• Force a redirect from HTTP to HTTPS in your site config.
• Verify transmissions are encrypted by checking for a lock icon and https:// in the browser URL bar.
• Configure supporting security features like HSTS headers.

HTTPS and SSL certificates should be considered mandatory in any threat model. Don‘t deploy a site without encryption!

Conclusion

In closing, WordPress security has come a long way over the years. The core software is actively maintained and vulnerabilities are quickly patched.

However, that doesn‘t mean every site is secure out-of-the-box. Configuration mistakes, poor operational practices and outdated perceptions expose many WordPress users to breaches.

Based on my extensive analysis and penetration testing, the top 5 loopholes you need to plug are:

1. Weak user passwords

2. Outdated software and lack of patching

3. Default database table prefixes

4. Unrestricted server user accounts

5. Lack of HTTPS encryption

Address these areas diligently by following security best practices, and you can drastically increase your WordPress site‘s security posture.

While risks like XSS, RFI and SQL injection require constant vigilance, shutting down the most common and easy-to-exploit attack vectors goes a very long way.

No software or environment can ever be made completely impenetrable, but prudent hardening and disciplined software development can get your WordPress install pretty darn secure.

So take action on closing these loopholes, and never let someone tell you WordPress can‘t be hardened! Feel free to reach out if you have any other WordPress security questions.