Cross-Site Request Forgery

Cross-Site Request Forgery (CSRF) is a web security Vulnerability that allows an attacker to trick a user into performing actions they did not intend on a web application where the user is authenticated. This attack occurs when a malicious request is sent from a different site, causing the target application to execute the unintended actions as if they were initiated by the victim.

CSRF Exploits the trust that a web application has in the user's browser. If the user is logged into a web application, the attacker can craft a malicious request that appears legitimate, such as submitting a form, changing settings, or transferring funds. When the victim's browser makes the request, the web application processes it using the victim’s authenticated session without further verification.

The purpose of a CSRF attack is to perform unauthorised actions on behalf of the user, potentially causing harm such as data manipulation, Privilege Escalation, or account compromise. Attackers often use CSRF to Exploit vulnerable web applications and trick users into performing actions that benefit the attacker while appearing to come from the victim.

CSRF attacks typically involve tricking the victim into clicking a link or loading a web page containing a malicious request. Since the user's browser automatically sends their Authentication cookies or tokens, the web application executes the request. Mitigation strategies include using anti-CSRF tokens, enforcing same-origin policies, requiring re-Authentication for sensitive actions, and implementing secure HTTP headers like Content Security Policy (CSP).

Examples of CSRF include a malicious link embedded in an email or website that causes a logged-in user to change their account email address, initiate a money transfer, or modify account settings on a target web application. Attackers may leverage CSRF to escalate privileges or Exploit other vulnerabilities by chaining attacks.

CSRF is challenging to detect because the malicious requests often appear to originate from the legitimate user. Effective prevention requires the use of anti-CSRF tokens to verify requests, implementing same-origin checks, and ensuring proper validation of user actions. Web developers must understand and address this Vulnerability to protect users from unintended actions and security risks.