Client-Side Security: The Attack Surface Your WAF Doesn't See
Your WAF guards your origin. But most modern website attacks live in the visitor's browser, over third-party code. Here's why client-side security is a distinct discipline.
Client-side security covers everything that happens in the visitor's browser after the page loads — JavaScript execution, third-party scripts, requests to external domains, and DOM manipulation. This is a surface that server-side defenses fundamentally do not see.
The industry's history is server-centric: WAF, IDS, file integrity monitoring. All of them look toward the origin. But a modern site loads dozens of scripts from external hosts — analytics, ads, A/B testing, chat, payments. Each is code you run with the full privileges of your page, and each is a potential entry point. When a tag manager or CDN script is compromised, your WAF is blind because the malicious traffic never passes through it.
The three main classes of client-side threats: web skimming/formjacking (form-data theft), drive-by downloads and exploit kits (malware delivery on page load), and ClickFix/fake CAPTCHA (social engineering executed by the user themselves). What unites them is that they execute in the client and are invisible to server-oriented infrastructure.
What good client-side protection looks like: an inventory of every third-party script and its connections; a strict Content-Security-Policy; Subresource Integrity for static dependencies; and — critically — continuous monitoring of what the page actually executes and who it connects to, as seen from a real browser, not a static scanner.
ExploitShield is built entirely around this surface. Rather than proxying your traffic, it re-renders monitored pages in real Chromium every 5 minutes, captures every JS body and every outbound destination, and enriches them with threat intelligence. The goal is simple: make the client-side attack surface as visible as the server side has been for decades.