Most organizations today can tell you what scripts are loaded on their website. Fewer can tell you what those scripts actually do. And that’s the problem. In the age of client-side attacks, relying solely on script name matching, hashes, or domain allow-lists is no longer sufficient. Attackers know how to hide in plain sight, injecting…
Published: July 26, 2025By: BreachFin Security Insights Team When we talk about client-side threats, most attention is given to JavaScript supply chain attacks, third-party scripts, and DOM manipulation. But there’s another growing blind spot: browser extensions. More than 70% of internet users have at least one extension installed. From password managers and coupon finders to…
Published: July 26, 2025By: BreachFin Security Insights Team In the world of DevOps and modern web development, change is constant. New features are pushed weekly, third-party libraries are updated silently, and marketing teams frequently tweak site tags without security oversight. All of this introduces what we call “script drift”—the gradual, unmonitored evolution of client-side JavaScript…
Modern websites are assembled from layers of third-party, fourth-party, and dynamically injected JavaScript. But while most organizations track their core scripts, few account for what we call “shadow scripts” — unmonitored, unapproved, or inherited JavaScript code that silently executes in the background. These aren’t just theoretical risks. Shadow scripts are often the first foothold in…
In the evolving world of client-side security, Content Security Policy (CSP) has long served as a frontline defense against cross-site scripting (XSS) and malicious JavaScript injection. But while CSP is a powerful mitigation tool, it is not impenetrable. Attackers in 2025 have become increasingly skilled at circumventing these headers—often without ever triggering a policy violation….
Introduction Many organizations believe that by using a hosted payment page (HPP) — like those offered by Stripe, PayPal, or Authorize.net — they’ve fully outsourced their PCI DSS risk. The logic is simple: “If the payment happens on their domain, we’re in the clear.” This assumption is not only wrong — it’s dangerously incomplete. What…
Introduction When you think of a supply chain attack, you probably think of SolarWinds or Log4Shell — backend incidents that ripple across entire ecosystems. But the same risk is now playing out in the browser — through the client-side supply chain. In this blog, we examine the surge in third-party frontend attacks and how businesses…
Introduction Security teams today excel at backend defense.They lock down APIs, enforce IAM, scan servers, monitor logs, and configure WAFs. But most of the risk in modern web applications is no longer only on the backend. It’s in the browser — where users interact with your brand, your data, and your code. This blog explains…
Introduction When companies deploy Content Security Policy (CSP), HTTP Strict Transport Security (HSTS), or X-Content-Type-Options, there’s often a sense of closure — “security headers are in place, job done.” But that mindset creates dangerous blind spots.Security headers are not a one-time setup.They are living configurations that must evolve with your frontend code, your vendors, and…
Introduction Security teams have long focused on locking down servers, hardening APIs, and encrypting data at rest. But in 2025, many attackers don’t need to breach your backend. They just watch your frontend — because nobody else is. This blog is a wake-up call for security leaders: if you aren’t monitoring what runs in your…
