CSS Injection Protection Solution

Protect your website from CSS injection attacks with intelligent client-side security and avoid data theft, as well as privacy and compliance violations

CSS injection attacks are difficult to perform but that does not mean that criminals are not actively using them to target your website. Ensighten is the leader at preventing CSS injection and other client-side attacks designed to steal your user's data, which is why our products are used to protect the world most valuable brands. 

Unlike other solutions, Ensighten’s technology does not rely on CSP driven or legacy signature-based mitigation approaches and instead utilizes modern, cutting edge browser-based detection to prevent attacks from taking place.

Solution highlights

CSS source verification
Verifies that all CSS files are from known, trusted and authorized sources, eliminating the ability to include malicious files from illegitimate locations
Intelligent analysis
Identifies specific types of data, such as credit card numbers and social security numbers, and prevents transmission to unknown destinations
Performant and lightweight
SaaS-delivered technology from highly scalable cloud infrastructure protects your website while maintaining the very best user experience
Network allowlist
Prevents data from leaving the web page except to approved destinations
Real-time analytics and reporting
Monitors all network requests and provides visibility into attack attempts, alerting you to potential issues
Comprehensive user interface
Allows easy configuration, rapid onboarding and low-maintenance protection

Comprehensive protection

Attackers are constantly adapting their methodologies, leveraging the complexity of the browser to find new ways to exfiltrate data. Our solutions enable protection against the following attacks:

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JavaScript injection
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Magecart
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Third-party vendor exploitation
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CSS injection
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Client-side keylogging
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Formjacking
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Web skimming
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Tag piggybacking
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Man-in-the-browser

How we compare

 

Ensighten  

Other CSS protection solutions

Standard website protections 

JavaScript injection mitigation

Also known as online skimming protection, web skimming protection and formjacking protection. Prevents data from being stolen through malicious code which has been injected into JS libraries which are used within websites  

Yes  

Yes  

Limited 

CSS injection mitigation

Prevents data from being stolen through CSS injection techniques, including brute-forcing stuffing

Yes  

Limited 

Limited 

Form replacement mitigation

Prevents attackers from replacing forms, such as check-out forms, with fake data-stealing forms by utilizing components such as iFrames 

Yes  

No  

No 

Malicious ainjection prevention

Prevents malicious ads being injected into websites through exploited components or through rogue browser extensions 

 

Yes  

No  

No 

Network allowlist 
Prevents data from being transmitted from a web page to remote locations other than those specifically defined in an allowlist 

Yes  

No  

No 

Full event-loop reporting 
Provides comprehensive reporting regarding client-side attack protection, including attempted and mitigated attacks 

Yes  

Limited 

No 

Simple setup and configuration  
Allows organizations to configure the solution simply by keeping configuration requirements to a minimum but still delivering a secure application 

Yes 

Limited 

No

Performant-focused solution 
Ensures that website performance is not affected by the implementation of an additional security layer 

Yes  

Caution

Caution 

 

What are CSS injection attacks? 

Cascading Style Sheet (CSS) files are generally considered safe by web developers and because of this their usage for malicious activity is often overlooked. CSS injection attacks are similar to online skimming exploits in that malicious code is injected into otherwise legitimate website files with the intention to perform illicit activity.

Oftentimes, because of the perceived inert risk of CSS, they can be overlooked in code audits and the inclusion of additional CSS files, or the modification of existing ones with malware can remain present on a website for significant periods of time.  

CSS injection attacks are a serious security concern because: 

  • Your infrastructure does not need to be breached for your website to be exploited; attackers can target the CSS files within the many third-party libraries utilized on your website
  • The browser is what processes the CSS files and there is often no visibility into the malicious activity, making detection difficult
  • You are liable for severe compliance penalties resulting from user data theft 

How CSS injection attacks work 

As websites evolve, so do the expectations to provide rich interfaces to users  and CSS plays a significant role in this. While historically used to define simple site-wide properties, such as fonts, background images and link colors, today’s CSS files can contain code blocks which can change actual web page content.

Element selectors for example can be used to inject content onto a page, enabling phishing attacks where users are tricked into downloading malicious executables. Properties such as background images can be set to remote URLs, allowing everything from a simple site defacement to the display of a malicious advertisement. Malicious CSS files can also be used to exfiltrate sensitive data from a web page by abusing otherwise legitimate functionality to enable brute-forcing techniques. 

 

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The risk of third-party CSS 

Modern websites leverage functionality from a myriad of sources, including code written in-house by an organization's developers and open source third-party libraries. While the benefits of using these external resources is significant, it also introduces security risks. 

Most third-party code is delivered from online repositories which cannot be adequately security vetted by the organizations making use of them, and many open source projects have codebases created by unknown developers from around the world. If any of these repositories were to suffer a breach or any of the developers were to be a malicious actor, then harmful code could be injected into an organization's website, circumventing any security measures they have in place. 

Prevent CSS injection

Get in contact to learn more about how Ensighten can prevent data leakage through a variety of client-side website attacks
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