Cross-Site Request Forgery (CSRF), also known as XSRF, Sea Surf, or Session Riding, is a type of cyber attack that exploits the trust a web application has in the user’s browser. It occurs when a malicious website or email tricks a user’s browser into executing an unwanted action on a different website where the user is authenticated. This can lead to various adverse outcomes, such as unauthorized fund transfers, password changes, and data theft, including the theft of session cookies.
In a CSRF attack, the attacker crafts a request that appears legitimate to the targeted web application. This request is then sent from the victim’s browser, which is already authenticated with the target site. Because the application cannot distinguish between legitimate requests from the user and forged requests from the attacker, it processes the malicious request as if it were a valid one. The attack relies on the user’s browser automatically including credentials like cookies or authentication tokens with the request.
CSRF attacks are often carried out through social engineering techniques, such as sending phishing emails or embedding malicious links in legitimate-looking websites. When the user clicks on the link or interacts with the malicious content, the forged request is sent to the target application without the user’s knowledge or consent.
To mitigate the risk of CSRF attacks, web developers can implement various security measures. One common approach is to use anti-CSRF tokens, which are unique, randomly generated values that are included in forms and verified by the server with each request. This ensures that the request originates from the application’s own interface and not from a third-party site. Additionally, setting the “SameSite” attribute on cookies can restrict their use to first-party contexts, reducing the risk of CSRF attacks.
Overall, understanding and defending against CSRF attacks are essential for maintaining the security and integrity of web applications and protecting users’ sensitive information.