A single compromised script can skim data for weeks, staying hidden from traditional security tools
CSPs, Crawlers, and JS agents were built for static threats. Modern attacks evade these approaches with dynamic code.
PCI DSS 4.0.1 requires client-side monitoring. GDPR penalizes companies for data leaks from malicious or misconfigured scripts.
Our hybrid proxy delivers advantages traditional tools can't match.
| Feature | cside | Traditional Solutions |
|---|---|---|
| Real User Monitoring | Sees actual user behavior and script execution in production | Crawlers only see sanitized versions of scripts |
| Targeted Attack Detection | Catches attacks aimed at specific user segments or time periods | Misses attacks between periodic scans |
| Script Analysis | Monitors actual script payloads and behavior in real-time | Only checks script sources, not what they do |
| Third-Party Risk | Detects when trusted providers are compromised | Assumes trusted sources are always safe |
| Dynamic Scripts | Handles dynamically generated and obfuscated code | Limited control over dynamic script execution |
| Attack Prevention | Analyzes scripts server-side where attackers can't interfere | Client-side analysis vulnerable to tampering |
| Historical Tracking | Complete audit trail of script behavior over time | Limited or no historical script tracking |
| Future-Proofing | Adapts to new attack techniques automatically | Requires updates to detect new threats |
"We moved to cside after paying for another solution by a large logo vendor when we were still using Magento. We knew that we've missed something, and cside flagged it even during the POC. I was skeptical at first but their approach is the only one that I found that works."
FAQ
Frequently Asked Questions
Client-side security protects users from threats that occur directly in their browser while visiting websites, particularly from malicious third-party scripts and dependencies. These scripts can steal credit card details, personal information, session tokens, and cause major compliance violations without your knowledge. Unlike server-side attacks that target your infrastructure, client-side attacks happen in real-time within users' browsers, making them invisible to traditional security tools like firewalls and server monitoring systems.
Third-party scripts are JavaScript files from external sources that websites use for functionality, analytics, advertising, and user experience enhancements. While these scripts improve website performance, even one malicious script can allow attackers to skim credit card details (Magecart attacks), steal login credentials and personal information, inject malicious redirects, and hijack user sessions. The risk is that these scripts execute with full website privileges, giving them access to everything users see and input on your pages.
Attackers compromise third-party scripts through supply chain attacks, taking over CDN domains, or injecting malicious code into legitimate scripts. They can then steal payment data in real-time, redirect users to malicious sites, capture form inputs and passwords, or inject fake payment forms. Many attacks are sophisticated and conditional, targeting only specific users or activating at certain times to avoid detection by security tools that only perform periodic scans.
Two notable examples include the British Airways Magecart attack in 2018, where compromised third-party scripts stole over 380,000 customers' credit card details, resulting in fines initially exceeding $200 million. More recently, the Polyfill.js hijack in 2024 saw attackers take over a widely-used CDN domain, redirecting users on over 100,000 websites to adult and betting sites. These attacks demonstrate how one compromised script can impact millions of users across thousands of websites simultaneously.
Traditional security tools like firewalls, server monitoring, and endpoint protection focus on server-side threats and network traffic. Client-side attacks execute entirely within users' browsers after the page loads, making them invisible to these conventional security measures. Additionally, many client-side attacks are conditional and sophisticated, only targeting specific users or activating under certain conditions, which means they can operate undetected for extended periods while affecting real users.
On financial websites, malicious third-party scripts can steal login credentials, personal information like SSNs and addresses, account numbers, transaction data, and payment details. They accomplish this by intercepting form submissions, capturing keystrokes, accessing browser storage, manipulating pages to create fake forms, and bypassing security measures. These scripts operate with full website privileges, making them incredibly dangerous for any site handling sensitive financial information.
According to Visa, 70% of all credit card theft now happens client-side, making this one of the most dangerous attack vectors facing organizations today. This statistic highlights why traditional server-side security measures are insufficient and why businesses need dedicated client-side security solutions. The shift toward client-side attacks reflects how attackers have adapted to bypass conventional security tools by targeting the browser environment directly.
Ask yourself this critical question: Can your security tools show exactly what data each third-party script collects, and can they detect a malicious payload that fires for only 1 in 1,000 visitors or targets just 5% of users after 5 p.m.? 99% of companies answer NO to this question. If your security tools only perform periodic scans or can't analyze actual script payloads in real-time, you're vulnerable to sophisticated, conditional client-side attacks.
