Cross-Site Request Forgery (CSRF) is a type of cyberattack where malicious actors manipulate users into performing unintended actions on a web application, such as submitting forms, clicking links, or making unauthorized changes, all without their knowledge or consent. These attacks exploit a web application’s trust in a user’s browser, tricking it into executing commands as though the user intentionally initiated them. The methods and outcomes of CSRF attacks can differ significantly depending on the specific tactics used, the vulnerability being exploited, and the particular target of the attack.
Understanding and Defining Cross-Site Request Forgery (CSRF) Attacks
A Cross-Site Request Forgery (CSRF) attack occurs when a malicious actor deceives an end user into unintentionally executing a malicious action or request. For everyday users, this could involve transferring funds, purchasing items, or changing login credentials such as passwords or email addresses. However, CSRF attacks can have even more devastating effects on a larger scale. When targeted at administrative accounts, these attacks can compromise an entire web application in a single blow.
Still wondering, “What is Cross-Site Request Forgery?” Keep reading for a detailed explanation of how CSRF attacks work, an overview of their various forms, and practical prevention strategies.
Understanding How Cross-Site Request Forgery (CSRF) Attacks Work
A Cross-Site Request Forgery (CSRF) attack is often executed using social engineering techniques. Attackers may send a malicious link via text message, email, or voicemail, tricking the user into performing an action the attacker desires. Alternatively, the attacker may exploit the user’s identity and authentication privileges to carry out an unwanted action on their behalf.
In a CSRF attack, the victim and the targeted website are manipulated. Many websites automatically include a user’s credentials in browser requests, such as session cookies, IP addresses, and Windows domain credentials. If the victim is logged into the site during the attack, the site usually cannot differentiate between a genuine request and a malicious one.
Beyond basic CSRF attacks, attackers may also perform a login CSRF. This specialized version of the attack forces an unauthenticated user to log in to an account controlled by the attacker. If the victim doesn’t realize they’ve been compromised, they might unknowingly provide sensitive data within the attacker-controlled account, such as credit card details or bank account numbers. The attacker can later access this account to retrieve the victim’s personal information and review their activity.
It’s important to note that the consequences of a successful CSRF attack depend on the capabilities of the compromised system and the victim’s account privileges. The more advanced and high-level the victim’s access, the more significant the attack’s potential impact.
How to Prevent a Cross-Site Request Forgery (CSRF) Attack
One of the most dangerous aspects of a successful CSRF attack is that the victim is typically unaware of it until it’s too late. By this time, the unauthorized transaction has already been completed. Users must be proactive to prevent a Cross-Site Request Forgery (CSRF) attack. Fortunately, there are effective prevention methods available.
The first step in preventing a CSRF attack is to check whether your system or web application framework offers built-in CSRF protection. If it does, ensure you enable it. If not, you can implement a CSRF token. A CSRF token is a secure, random string—such as a synchronizer or challenge token—that helps application servers determine whether an HTTP request was legitimately generated through the application’s user interface or was forged.
For effectiveness, each user session must be assigned a unique CSRF token. As users interact with the site and submit requests, the application server checks whether the request includes the correct CSRF token. If the token doesn’t match, the server rejects the request, preventing the CSRF attack from succeeding.
To further understand how malicious actors exploit vulnerabilities in web applications, check out SiteLock’s blog post on “What Is an Attack Vector?“