What is XSS and what are the three main types?

beginner

Re-explain

Cross-Site Scripting (XSS) allows attackers to inject malicious scripts into web pages viewed by other users.

Three main types:

Stored XSS (Persistent): Malicious script stored on server
- Example: Comment section storing <script>alert('XSS')</script>
Reflected XSS (Non-persistent): Script reflected from request
- Example: Search parameter displayed without encoding
DOM-based XSS: Vulnerability in client-side JavaScript
- Example: document.write(location.hash.substring(1))

Impact: Session hijacking, credential theft, defacement, malware distribution

Prevention: Input validation, output encoding, Content Security Policy (CSP), sanitization

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