What is Cross-Site Scripting?

Cross-Site Scripting (XSS) refers to the injection of malicious scripts into web pages that are viewed by users. It takes advantage of vulnerabilities in web applications that do not properly validate or sanitize user inputs. When a user visits a compromised page, the embedded script can execute in the context of the user’s browser, potentially leading to data theft, account hijacking, or the spread of malware.

This type of attack is particularly concerning because it can affect users who trust the website hosting the vulnerable content. For instance, if a user logs into a site and is tricked into executing a script, the attacker could gain access to session cookies or other sensitive information, allowing for unauthorized actions such as impersonating the user.

Understanding XSS is crucial for developers and security professionals to implement measures such as input validation, output encoding, and content security policies to mitigate these risks.