Demo of cyber security risk of XSS

What is XSS and Why Is It Risky?

XSS happens when a website doesn’t properly “clean” (sanitize) user inputs, like search queries or comments. An attacker can inject JavaScript code, which runs when you visit the page. Risks include:

• Stealing sensitive info: Like login cookies, allowing hackers to impersonate you.
• Redirecting you: To fake sites for phishing or malware.
• Altering the page: To spread misinformation or scams.
• Exfiltrating data: Sending your info to a hacker’s server quietly.

Real-world examples: In 2018, hackers used XSS on British Airways’ site to steal credit card details from 380,000 users. Or the 2005 MySpace worm that spread via profiles.

Modern browsers and sites (like WordPress with proper plugins) mitigate this, but unpatched vulnerabilities still exist. Always sanitize inputs and use Content Security Policy (CSP)!

The Demo: Normal vs XSS

I’ve created an interactive example below. It mimics a simple “search” feature on a site (think a blog like mine at lazy-guy.xyz).

• Normal Link: Simulates safe access. Clicking shows harmless content—no code injection, no risks. This is how secure sites handle inputs (e.g., escaping special characters).
• Problem Link (XSS Simulation): Mimics a vulnerable site where input isn’t sanitized. Clicking “injects” a script that:
  1. Executes code automatically (basic alert).
  2. “Steals” cookies (shows them in an alert—harmless display).
  3. “Sends” data to a hacker (logged to console; alert notifies).
  4. “Redirects” you (alert warns; no actual redirect).

Comparison: Normal vs XSS

Here’s a breakdown of what happens in each case:

Aspect	Normal (Safe)	XSS (Vulnerable)	Real-World Impact Example
What You See	A simple message appears below the link. Everything stays on the page.	Text appears, then alerts pop up one by one, with a console log.	In the demo, alerts are visible for education—in real attacks, everything happens silently, like the 2019 Magecart XSS on hundreds of e-commerce sites, stealing payment info from millions.
Code Execution	No unexpected code runs. The site controls everything.	Injected script executes automatically.	Hackers gain browser control, as in the 2014 Forbes XSS where visitors were redirected to exploit kits, infecting devices with malware.
Data Handling	No access to sensitive info like cookies.	“Steals” and displays cookies.	Enables session hijacking; e.g., the 2021 Twitter XSS allowed account takeovers, leading to spam or data leaks.
Background Actions	None—transparent and safe.	Simulates sending data invisibly.	Quiet theft, like in the 2018 Eventbrite XSS that exfiltrated user emails and passwords to attackers.
Further Risks	Ends there; no escalation.	“Redirects” via alert.	Leads to phishing chains; e.g., the 2015 eBay XSS redirected users to fake login pages, resulting in credential stuffing attacks.

In the demo, the XSS uses innerHTML unsafely to inject code—never do this in real apps! Use textContent or libraries like DOMPurify for safety.