A typical point of entry is when a malicious actor compromises a third-party service your website uses. Here's the process: your server sends the web page, and your browser requests hundreds of external resources like analytics scripts, marketing tools, and payment processors. Then, an attacker can intercept just one of these requests and inject malicious code instead of the legitimate script.
Malicious scripts can also be injected through adverts, ad networks are essentially JS distribution networks for hire. A script on an ad network can steal credit card information and take sensitive tokens like session tokens. Therefore, if you have webpages where adverts and payments cross, it is best to be extra careful and implement a strict client-side security.
How do client-side attacks actually happen?
Compromising a third-party service your website relies on is one common way attackers get in.
Why can't traditional security tools detect client-side threats?
Firewalls, WAFs, and vulnerability scanners are traditional security tools used to protect your server, but they cannot see what's happening in your users' browsers.
What's the difference between client-side security and server-side security?
Server-side security protects your infrastructure, while client-side security focuses on where your application actually runs, inside your users' browsers.
What's the difference between client-side security and application security?
Client-side security is a critical subset of AppSec that focuses on protecting applications where they actually execute--in users' browsers.