CSRF

Cross-Site Request Forgery (CSRF) is a type of attack where a malicious site causes a user's browser to perform unwanted actions on a trusted site while the user is logged in.

How CSRF Works

1. A user logs into a trusted website, creating an authenticated session.
2. An attacker crafts a malicious link or form designed to target the trusted website.
3. The attacker presents this link or form to the user through various means, such as email, ads on legitimate websites, or instant messages.
4. When the user clicks the malicious link or submits the form, their browser sends a request to the trusted website, executing the attacker's action without the user's consent.

Example

Consider a banking website that allows users to transfer funds between accounts. An attacker could create a malicious link that targets the bank’s transfer page. If a logged-in user clicks the link, their browser would send a request to transfer funds to the attacker's account, unbeknownst to the user.

In reality, many banks implement additional verification measures, such as SMS codes or one-time passwords (OTPs), to enhance security and prevent unauthorized transactions. These measures are crucial in protecting users against CSRF attacks and other forms of fraud.

Prevention

One effective method to prevent CSRF attacks is the Synchronizer Token Pattern. This involves generating a unique, unpredictable token for each user request, storing it in a session variable, and including it as a hidden field in forms. When handling form submission, the server verifies the token against the session to ensure that the request originates from the original website.