Ethical Hacking Essentials Practice Test

Cross-Site Scripting (XSS) is a significant application security threat that occurs when an application includes untrusted data in a new web page without adequate validation or sanitization. In XSS attacks, an attacker injects malicious scripts into content that is then served to users. When users view the compromised page, the malicious script executes in their browsers as if it were a trusted part of the website, which can lead to unauthorized access to cookies, session tokens, or even control of the user's browser.

This vulnerability arises primarily because modern web applications often dynamically generate content using user inputs, which, if not properly sanitized, can allow attackers to embed harmful scripts. The risk intensifies when user-generated content is rendered on a web page without validating it, leading to potential exploits that can compromise data integrity, confidentiality, and even user sessions.

Understanding XSS is vital in application security, as it emphasizes the necessity of validating and sanitizing all user inputs before including them in webpage content to prevent the execution of malicious scripts.