Have you ever heard of clickjacking? This clever attack tricks users into clicking on hidden, malicious elements by overlaying them on-screen over legitimate buttons or links. Hackers abuse this to silently steal data or access.
It may sound harmless, but clickjacking has been used to target banks, webmail providers, social networks, and more. Even an innocent "Like" or "Share" click can turn into a compromised account.
The good news? Clickjacking is easy to mitigate by implementing a strong content security policy (CSP) using the frame-ancestors directive. Let‘s look at how to properly configure this across Apache, Nginx, and WordPress.
Why Clickjacking is a Persistent Threat
While clickjacking has been around for over a decade in the web security world, it remains a common attack vector. Just last year, clickjacking vulnerabilities were uncovered on PayPal, Cloudflare, and other major sites.
According to statistics from WhiteHat Security, over 40% of websites still contain some clickjacking vulnerabilities. And Verizon‘s 2021 Data Breach Investigations Report found that social engineering-based attacks like clickjacking continue to grow year over year.
The reason clickjacking persists is many websites still aren‘t using effective anti-framing defenses. Relying solely on alternate headers like X-Frame-Options leaves gaps. Plus, clickjacking techniques and attack libraries continue advancing.
This is why OWASP (the Open Web Application Security Project) recommends a strong content security policy with the frame-ancestors directive as a core defense in their top 10 web application security risks list.
How Frame-Ancestors Block Clickjacking
By default, websites can be embedded seamlessly into iframes, frames, objects and more by any domain. This allows malicious sites to layer hidden interface elements over legitimate buttons to trick clicks.
The frame-ancestors directive restricts which domains can embed pages from your domain – stopping unauthorized framing dead in its tracks.
For example, this policy only allows the current site to embed itself but blocks all other domains:
Content-Security-Policy: frame-ancestors ‘self‘Tightly restricting frame ancestors hardens your application against UI redress methods like clickjacking. Let‘s look at implementing correct policies based on your stack.
Step-by-Step Implementation Guide
Before we continue, ensure you have a safe testing environment to validate changes without impacting production traffic or users.
Apache Configuration
On Apache, we‘ll use the mod_headers module to inject the CSP. Enable mod_headers if needed:
a2enmod headers
systemctl restart apache2Add your policy within applicable or virtual host sections:
Block All Framing
Header set Content-Security-Policy "frame-ancestors ‘none‘;"Allow Self Framing Only
Header set Content-Security-Policy "frame-ancestors ‘self‘;"Allow Specific Sites
Header set Content-Security-Policy "frame-ancestors ‘self‘ https://example.com;" After saving changes and restarting Apache, the policy will be live.
Nginx Configuration
For Nginx, insert your CSP ruleset using the add_header parameter instead within your server block:
Block All Framing
add_header Content-Security-Policy "frame-ancestors ‘none‘;";Allow Specific Sites
add_header Content-Security-Policy "frame-ancestors *. mysite.com *.approvedpartner.com"; Once implemented and after an Nginx reload, all framing attempts will respect the new ancestors.
WordPress Protection
If your WordPress site runs on managed hosting, simply install a security plugin like Wordfence or iThemes Security to add anti-framing headers.
For self-hosted WordPress, use the aforementioned Apache or Nginx guides depending on your stack to set the CSP header at the web server level. This offers the strongest enforcement outside WordPress itself.
You may also benchmark different WordPress security plugins to find one that best supplements your policy framework.
Validating Correct Configuration
Verifying that frame-ancestors is working correctly helps identify any issues early on.
Manually attempt to iframe a protected page from an outside website – you should see blocking or errors on disallowed domains based on your policy.
Online tools like SecurityHeaders.com can also scan sites for proper CSP implementation across endpoints. Use these frequently after initial setup and when introducing new domains.
I suggest reviewing reports in browser DevTools too for warnings around unsafe framing attempts blocked by the policy. This helps confirm effectiveness.
Clickjacking Defense – Just the Beginning
A tight Content-Security Policy with frame-ancestors to prevent abusive framing offers tremendous protection against clickjacking, UI redress attacks and more.
But don‘t stop there! Consider requiring other powerful headers like X-XSS-Protection, Referrer-Policy, and Feature-Policy to further lock things down. Strict-Transport-Security (HSTS) is also a must on sites handling logins or financial data.
Content Security Policy remains an emerging standard – stay on top of new directives and proposals to expand coverage over time. Revisit your policies frequently as new threats emerge.
I hope this guide gives you a streamlined reference for applying robust clickjacking protection on your websites and web applications. Feel free to reach out if you have any other questions!
