XSSRF

XSSRF is a cybersecurity vulnerability that combines Cross-Site Scripting (XSS) and Cross-Site Request Forgery (XSRF) techniques. While distinct, their combined exploitation can lead to more severe impacts on web applications and their users. XSS involves injecting malicious scripts into a website, which are then executed by unsuspecting users' browsers. XSRF, on the other hand, tricks a user's browser into executing an unwanted action on a web application in which the user is currently authenticated.

The XSSRF vulnerability arises when an attacker can leverage an XSS flaw to bypass XSRF protection mechanisms. For instance, an attacker might inject a script into a vulnerable website that, when executed by a victim, makes an unauthorized request to another site on behalf of the victim. This request could be a state-changing action such as transferring funds, changing account settings, or posting content. The victim's browser, having authenticated credentials for the target site, sends these requests without the victim's explicit consent.

The impact of XSSRF can be significant, leading to data breaches, unauthorized transactions, and reputational damage for affected organizations. Preventing XSSRF involves a multi-layered security approach. Robust input validation and output encoding are crucial to mitigate XSS. For XSRF, implementing anti-CSRF tokens, checking the `Origin` and `Referer` headers, and using SameSite cookie attributes are effective defenses. Developers must be vigilant in addressing both vulnerabilities to protect their applications and users.