What is cross-site request forgery (CSRF)?

Cross-site request forgery (CSRF) is a type of security vulnerability that allows attackers to trick users into performing actions they did not intend. This is done by making a request on behalf of the (logged in) user without the user’s knowledge or consent.

CSRF attacks often involve tricking the user into clicking on a malicious link or visiting a malicious website. Once the user is on the site, the attacker can use his existing session information to make requests on his behalf, potentially allowing the attacker to steal sensitive information or perform actions that the user did not intend to do.

A common example of a CSRF attack is an attacker sending a malicious email to a user containing a link that appears to be legitimate. When the user clicks on the link, he is redirected to a website operated by the attacker, where the attacker can use his existing session information to perform actions on his behalf, such as changing a password.

To prevent CSRF attacks, it is important for websites to implement proper security measures. This can include using unique, unpredictable tokens for each request (called CSRF tokens), checking the HTTP referrer header to verify that the request comes from a trusted source, and implementing strict security policies for handling sensitive actions.

It is also important that users exercise caution when clicking on links and visiting websites, especially if they are unsure of the source or legitimacy of the link. By taking these precautions, users can protect themselves and their information from misuse by attackers.