Which type of attack takes advantage of vulnerabilities in validation?

Cross-site scripting (XSS) attacks exploitinput validation vulnerabilitiesin web applications. These vulnerabilities occur when an application fails to properly validate, sanitize, or encode user-supplied input before including it in web pages. As a result, attackers can inject malicious scripts that are executed in the browsers of other users.

XSS attacks commonly occur through form fields, URL parameters, cookies, or HTTP headers. Once executed, malicious scripts can steal session cookies, capture keystrokes, redirect users to malicious sites, or perform actions on behalf of the victim.

ARP spoofing and DNS poisoning target network-level trust relationships, not application input validation. Pharming redirects users to fake websites by manipulating DNS or host files, again unrelated to input validation.

Preventing XSS relies heavily on strong input validation, output encoding, content security policies (CSP), and secure coding practices. OWASP and NIST explicitly identify XSS as a validation-related vulnerability and emphasize defensive coding as the primary mitigation.