XSS Hunting: Risks of document.write and Detection Strategies
The document.write method in JavaScript remains a critical vector for Cross-Site Scripting (XSS) vulnerabilities. While it dynamically injects HTML content, improper handling of user input can enable attackers to execute arbitrary scripts. This article explores practical techniques to identify and mitigate risks associated with document.write, supported by real-world cases and defensive frameworks. 1. Why document.write Enables XSS Core Risks document.write directly renders unvalidated strings into HTML, creating vulnerabilities when: Untrusted input sources (URL parameters, form fields) are used without sanitization. Inadequate escaping allows characters like < or > to bypass defenses. Dynamic contexts (search results, error messages) amplify injection opportunities. Example: ...