Cross-site request forgery (CSRF), also known as sea surf or session riding, is a similar malicious attack on a website or web application that involves a trusted user sending unknown commands.
CSRF attacks use a web application’s trust in a user’s browser. When a user logs into a web application, the application assumes that any requests sent by the user’s browser are valid. An attacker can gain control of this trust by tricking the user into visiting a malicious website that sends a CSRF request to the trusted application.
The malicious website can trick users into visiting it by sending them a malicious link in an email, instant message, or social media post. Once the user clicks on the link, the malicious website will send the CSRF request to the trusted application.
The CSRF request will be sent with the user’s session cookie, allowing the attacker to impersonate the user and perform actions on their behalf. The attacker could, for example, use the CSRF request to withdraw funds from the user’s bank account, change the user’s password, or make unauthorized purchases.
Preventing CSRF Attacks
There are several ways to prevent CSRF attacks. Preventing CSRF attacks necessitates a combination of defensive measures implemented on both the server and client sides.
Implement Synchronizer Tokens
Using synchronizer tokens is one of the most effective ways to prevent CSRF attacks. This method includes a unique token with each request that modifies the server-side state. This token is usually hidden in a form or attached as a custom HTTP header. When the server receives the request, it checks the true nature of the token to ensure it matches the user’s session. The server rejects the request if the token is missing or invalid.
Use Double Submit Cookies:
Double-submit cookies, like synchronizer tokens, involve embedding a token within the user’s browser and server-side session. When a request is sent, the server compares the token from the cookie to the token in the request body or header. Because attackers cannot access or manipulate the cookie’s value due to cross-origin restrictions, this technique prevents them from forging requests.
Implement Same Site Cookies
Cookies are essential to CSRF attacks because they are sent with each request to the same domain. Setting the “SameSite” attribute for cookies to “Strict” or “Lax” limits their scope and prevents unauthorized access. Cookies are only sent in a first-party context in strict mode, while lax mode allows some exceptions for specific cross-origin requests, such as those triggered by links or top-level navigation.
Implement CAPTCHA:
Including CAPTCHA challenges in critical actions or sensitive forms can significantly reduce the risk of CSRF attacks. To verify their identity, CAPTCHAs require users to complete a challenge, such as identifying distorted letters or selecting specific images. Because most CSRF attacks are robotic, the presence of a CAPTCHA can effectively prevent malicious attempts.
Restrict HTTP Methods
Another precaution is to limit the use of specific HTTP methods for sensitive actions. For example, sensitive operations such as account deletion or money transfers should only be permitted via HTTP POST requests. The impact of CSRF attacks can be reduced by limiting using potentially dangerous HTTP methods such as GET, PUT, DELETE, and so on.
Regular Security Audits
It’s essential to perform regular security audits and vulnerability assessments on web applications to detect and address potential CSRF vulnerabilities. It aids in ensuring that preventive measures are effective and up to date. Penetration testing, code reviews, and security scans can reveal security flaws and provide helpful insights for improving the application’s security posture.
Here Are Some Additional Tips for Preventing CSRF Attacks:
1. Use caution when clicking on unnecessary links. If you get an email or an instant message from someone you don’t know, don’t click on any of the links in the message.
2. Keep your browser and operating system up to date.
3. Use a security solution with CSRF protection. A security solution can help protect your account from unauthorized access by blocking malicious requests.
You can help protect yourself from CSRF attacks by following these guidelines.