Cross-site request forgery (CSRF) attacks represent one of the most serious and widespread threats to web applications today. The consequences of a successful CSRF attack can range from data theft to account hijacking, depending on the access rights of the account accessed.
To reduce the risk of a CSRF attack, Adrien de Beaupre and Jeremiah Grossman, two of the most respected security research experts, have developed a set of best practices designed to defend against CSRF attacks.
The first step in defending against CSRF attacks is to understand the attack itself. CSRF attacks attempt to exploit the trust that exists between websites and browsers, by making a malicious request to a website on behalf of a legitimate user. For example, a CSRF attack might attempt to trigger a transfer of funds from a user’s bank account by making an authenticated request to the bank’s website.
Once you understand the attack, the next step is to implement measures to prevent it. Adrien de Beaupre and Jeremiah Grossman recommend implementing an anti-CSRF token system, which is typically composed of randomly generated tokens that are sent to the user’s browser and then included in any requests the user makes. This token system is designed to prevent CSRF attacks by ensuring that only requests that include the correct token are accepted by the website.
In addition to implementing an anti-CSRF token system, Adrien de Beaupre and Jeremiah Grossman recommend taking steps to reduce the number of privileged accounts on a website. By reducing the number of privileged accounts, the risk of a successful CSRF attack is also reduced.
Finally, Adrien de Beaupre and Jeremiah Grossman recommend that websites employ a defense-in-depth strategy when it comes to security. This means implementing multiple layers of security, such as a web application firewall and a content security policy, to protect against various types of attacks.
By following the best practices recommended by Adrien de Beaupre and Jeremiah Grossman, organizations can significantly reduce the risk of a successful CSRF attack. While no security measure is perfect, taking proactive steps to defend against CSRF attacks will go a long way toward protecting your organization from this serious threat.