Cross-Site Scripting (XSS) — Free Cyber Security Tutorial
Learn Cross-Site Scripting (XSS) in Cyber Security with a free, beginner-friendly tutorial, examples and practice for Indian students on Syllab.in.
TL;DR: Learn Cross-Site Scripting (XSS) in Cyber Security with a free, beginner-friendly tutorial, examples and practice for Indian students on Syllab.in.
Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated
Cross-Site Scripting (XSS) in Cyber Security
Cross-Site Scripting (XSS) is a vulnerability where attackers inject malicious JavaScript code into web pages viewed by other users, allowing them to steal cookies, session tokens, or perform actions on behalf of users.
XSS occurs when user input is displayed on a web page without proper escaping or sanitization. Attackers can inject scripts through comments, forms, URLs, or any user-controlled content.
There are three types: Stored XSS (malicious code saved in database), Reflected XSS (code in URL parameters), and DOM-based XSS (vulnerability in client-side JavaScript).
Prevention includes escaping user output, using Content Security Policy (CSP) headers, validating input, and using templating engines that auto-escape by default.
Cross-Site Scripting (XSS) — Syntax
Vulnerable: <div>" + userComment + "</div> Safe: <div><%- userComment %></div> // HTML-escaped
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