Cross Site Scripting

Description

Cross-Site Scripting (XSS) attacks occur when malicious scripts are injected into trusted websites, often through user inputs, and executed in the browsers of other users. These attacks exploit vulnerabilities in web applications that fail to properly validate or encode user input, allowing attackers to steal sensitive information, hijack user sessions, deface websites, and more.

Recommendation

To mitigate XSS attacks, always sanitize and encode user input before rendering it in HTML. Utilize libraries specifically designed for sanitizing and encoding untrusted data. The OWASP XSS Prevention Cheat Sheet provides comprehensive guidance on preventing XSS vulnerabilities. Additionally, consider implementing security controls provided by the OWASP ESAPI project, which offers reusable security components in multiple programming languages.

References

• CWE-20
• CWE-79
• OWASP 2021-A3
• OWASP: Cross Site Scripting (XSS)
• OWASP: ESAPI project
• OWASP: XSS Prevention Cheat Sheet