Securing WordPress Sites: An In-Depth Guide

Understanding WordPress Security Threats

WordPress powers over 30% of all websites, making it an attractive target for hackers. Sites running outdated WordPress software and plugins are especially vulnerable. Common attack vectors targeting WordPress sites include:

• Brute force attacks – Repeated login attempts to gain admin access
• SQL injection – Inserting malicious SQL code into forms and URLs
• Cross-site scripting (XSS) – Injecting client-side scripts into pages
• Cross-site request forgery (CSRF) – Tricking users to unknowingly run malicious code
• File inclusion vulnerability – Tricking WordPress to reveal sensitive files

These attacks allow hackers to steal sensitive data, deface sites, install malware, launch spam campaigns, and more. Even small vulnerabilities can lead to complete site takeover. WordPress sites left unpatched are targets due to the widespread use of outdated plugins and themes vulnerable to known exploits.

Most Frequent Vulnerabilities Exploited in WordPress

Plugins extend WordPress functionality but also increase the attack surface. Flaws in popular plugins allow mass exploitation. The most targeted plugins include:

• Contact Form 7 – Files uploaded through forms can allow malware upload.
• WordPress SEO by Yoast – Stored cross-site scripting vulnerability.
• WP Symposium – Multiple SQL injection issues.
• MailPoet Newsletters – Vulnerable to cross-site scripting attacks.

Outdated themes and WordPress core also pose risks. Obsolete versions of WordPress, themes, and plugins contain known security bugs that have since been patched in updated versions. Failing to properly update precisely when new fixes are released puts site security in jeopardy.

Consequences of a Compromised WordPress Site

The implications of a hacked WordPress site extend beyond just embarrassment and downtime. Specifically:

• Malware infection – Backdoors allow remote access for ongoing exploitation.
• SEO damage – Blacklisted sites drop search engine rankings.
• Server resource misuse – WordPress could be used to mine cryptocurrency.
• Reputational harm – Visitors lose trust after malware jump scare.

Without adequate WordPress hardening, sites remain prone to repeat attacks. Proactively securing WordPress prevents severe consequences down the line.

Hardening Your WordPress Site

Hardening WordPress sites involves multiple layers of protection to block attacks, limit damage, and aid recovery. Key hardening techniques include:

Keeping WordPress and Plugins Updated

Hackers exploit known flaws that have been patched in newer software versions. By updating to the latest releases, those vulnerabilities are closed. Enable automatic WordPress updates to stay on top of new security fixes.

Equally important is keeping all plugins and themes updated. Click “Check for updates” on the Plugins page to patch plugin vulnerabilities when fixes become available. Consider removing unused plugins entirely to reduce your site’s attack surface.

Choosing Secure Hosting With Automatic Backups

Your web host provides the foundation for securing WordPress. Ensure your hosting provider offers:

• Automatic daily backups to facilitate recovery
• Server firewall rules to block suspicious traffic
• SSH key authentication preventing stolen passwords
• DDoS mitigation stopping volumetric floods

A secure host limits damage from compromised sites until they can be restored from backup. Costly business downtime is minimized.

Enabling SSL to Encrypt Traffic

Install an SSL certificate to enable HTTPS across your entire WordPress site. Forced SSL redirects all requests over HTTPS to prevent insecure HTTP access. SSL encrypts sessions to keep sensitive visitor data private from eavesdroppers.

Free certificates from Let’s Encrypt quickly activate HTTPS security alongside auto-renewals. SSL seals also boost search engine trust rankings.

Securing Admin User Accounts

The administrator account permits site-wide changes, making it a prime target. Avoid account compromise by:

• Enabling two-factor authentication (2FA)
• Limiting admin access only from certain IP addresses
• Changing the default “admin” username to be less obvious
• Granting limited access for site editors and authors

Likewise, enforce strong passwords over 12 characters containing numbers, cases, and symbols without dictionary words.

Limiting Login Attempts to Prevent Brute Force

A common attack tries cracking passwords by brute force guessing. Limit failed login attempts via plugin to lockout IP addresses after just 6 failures for a duration like 60 minutes. This drastically slows attackers.

Alternatively, display CAPTCHAs after several failures to require human input. Either approach frustrates brute force enough to convince attackers to seek easier sites.

Securing Your Website Code

While hosting, SSL, and login policies strengthen WordPress access controls, software vulnerabilities also must be addressed. Improving code security involves:

Sanitizing and Validating User Input and Uploads

All user input and uploads should be sanitized before inclusion into WordPress to prevent abuse. Specifically:

• Validate and sanitize GET and POST input data
• Check file types and contents before uploads
• Set maximum image upload sizes
• Restrict authorizations to modify certain content

This limits uploads of PHP shells and blocks embedded script contents from hijacking sites via reflected XSS. Input validation shuts down leading web app vulnerabilities.

Avoiding Dangerous PHP Functions

Enable PHP hardening in wp-config.php by disabling dangerous functions like:

• eval() – Executes arbitrary PHP code
• create_function() – Deprecated method to create functions
• serialize() and unserialize() – Manipulated during object injection attacks
• exec() – Executes system level commands
• passthru() – Allows system command execution

These methods have legitimate uses but are more often abused by attackers. Disallowing cuts off malicious code execution.

Using Nonces and CAPTCHAs for Forms

WordPress nonces and CAPTCHAs thwart CSRF attacks against site forms. Nonces confirm form requests originate from your site domain not remote sites. CAPTCHAs block automated spam/brute force bots.

Enable both across user-facing forms like login, contact forms, comments, etc. This protects taking administrative actions like deleting accounts without consent.

Disabling File Editing and Script Execution

Hacked sites often have files maliciously modified or executable payloads uploaded. Restrict site permissions to minimize impact by:

• Disabling editing of plugin/theme files
• Setting wp-content files as read-only
• Restricting file execution to just whitelisted file types

This limits damage an attacker can inflict by hiding unauthorized changes or preventing payload execution.

Monitoring and Detecting Threats

Continuously monitoring WordPress sites enables detecting attacks proactively before major consequences:

Enabling Login Notifications

Require admin emails on all user logins to reveal brute force attacks in real-time. Log timestamps and IP addresses for auditing. Lockout regions like China/Russia via IP deny list if repeated unfamiliar locations appear.

Checking Files for Unauthorized Changes

File change monitoring tools like Tripwire create file integrity hashes initially. Alerts trigger if current hashes differ from the baseline revealing malicious edits. Integrity checks uncover web shells, backdoors, and other signs of hacks.

Using a Web Application Firewall

A WAF blocks known WordPress application layer attacks by monitoring all traffic. Common attack patterns like SQL injection and XSS trigger automated blocking rules. Cloud-hosted WAF services require no server configuration yet still halt threats.

Monitoring Site Traffic for Signs of Infection

Sudden upticks in site traffic may reveal botnets now using your site resources. Similarly, strange outbound traffic likely signals exploitation. Enabling access logs in WordPress and your hosting provider illuminates traffic changes warranting incident response.

Recovering From a WordPress Security Incident

Despite best efforts, WordPress sites still get compromised. Minimize business disruption by preparing an incident response plan for WordPress breaches including:

Identifying Cause and Extent of Breach

Determine attack entry points by reviewing web server access logs showing requests right before incident. Look for signature patterns like SQLi payloads. Check when users report seeing issues to pinpoint start times.

Likewise inspect altered files and databases to gauge impacts. Document affects while preserving evidence like hacked files and user reports demonstrating damage.

Restoring From Backups to Undo Changes

Restore compromised files from pristine, pre-breach backups assured as malware-free. Clean DB imports also revert data destruction. Confirm restored data integrity checks match initial hashes proving recreation from backup.

Rebuild staging servers when unsure if backups got poisoned too. Test thoroughly before re-launching live sites restored from backup.

Resetting All Account Passwords

Require all WordPress users reset passwords assuming credentials got compromised for reuse elsewhere. Lockout previous passwords from change forms. Send email confirmations with new auto-generated passwords expiring in 72 hours.

Prepare help desk to field password reset requests avoiding product team distraction. Monitor actions by newly activated accounts closely for anomalies.

Conducting Security Audits Before Relaunching

After fully restoring sites, yet before opening access again, perform comprehensive WordPress security audits checking:

• Plugin/theme updates applied
• Server and WordPress permissions locked down
• New passwords across all accounts
• File integrity verification via Tripwire
• WAF and login notification enabled

Confirm no lingering vulnerabilities remain permitting repeat intrusions after relaunch. Iteratively harden sites based on audit findings.