Cross-Site Forgery Attack

Cross site forgery attack also referred to as one-click attack or session riding, is a technique that fools a web browser into launching an unwanted action.

What is CSRF Attack?

Cross site request forgery attack or xsrf is an attacking technique that tricks the web browser into launching an unwanted action within the application through which a user logged in. Successful CSRF DDoS attack can be disastrous to both a regular user and a business.

It can translate to disturbed client relationships, unauthenticated fund transfers, data, and identity theft, and modified passwords too. Cross-site forgery attack is a social engineering method, such as a malicious email or link that tricks the target into sending forged requests to a server. As the application authenticates the genuine user, it becomes challenging to differentiate between a legitimate user and the forged one.

Here’s how cross-site forgery takes place:

  1. The attacker forges a request for a financial transaction to a web application
  2. The attackers integrate a link underneath the email and send it to visitors who may open the email
  3. The visitor clicks on the malicious link, sending the request to the website
  4. The website authenticates the cross-site request and transfer funds from the visitors account to the attacker

Csrf Attack Example

Before executing the attack, the victim makes sure the application can be used to create an assault, that is, to make a forged request appear as legitimate as possible. For instance, the attacker would generate a get request for, let’s say, transferring a 100$ to his bank account.

A hacker will modify the script, so it results in the money transfer into his account. The black actor can make an innocent-looking web address completely genuine. Next, he can disseminate the hyperlink to thousands of users. Whoever presses that link will eventually lose their money from their bank accounts, and transmit it to the attacker's account.

Ensure that if the bank’s website is only using the method post request, it’s impossible to make malicious requests using the a href HTML tag. However, the form tag can be used to execute the malicious script automatically.

Methods of CSRF Mitigation

  • Log off-web applications when you aren’t using
  • Protecting usernames and passwords
  • Denying browsers from saving your passwords
  • Prevent parallel surfing while signed In into the application

For web apps, many solutions exist to block malicious traffic and avoid csrf attacks. The most common mitigation methods include generating a token ID for each request ever made. These are regularly checked and verified by the server. These servers block session requests having duplicate or missing values. Similarly, a request that doesn’t match the token ID is preventing from reaching the application.

Another method to mitigate DDoS csrf attacks is the double submission of cookies. Similar to using unique tokens, random tokens are attached to each cookie and request parameter. The server then authenticates the tokens before granting any access to its servers.

While effective, tokens can be transparent across many points, for instance, browser history, HTTP log files, referrer headers, if the protected site matches to the external URL. These vulnerabilities make tokens a less full-proof solution.
Learn more about DDoS Protection

What are CSRF tokens?

A csrf token is a unique and unanticipated value generated by the server-side application and sent to the client in a way that is included in the HTTP request made by the client. When the client initiates the request, the server-side application authenticates that the request has the included unique token and denies the request if the token isn’t received.

CSRF token can prevent DDoS CSRF attacks by making it next to impossible for the attacker to fully produce an HTTP request suitable for transmitting to the victim. Since the attacker cannot determine nor anticipate the token value, they cannot generate a request with all the necessary parameters that are extremely mandatory for the application to grant the request.

What is the difference between cross-site scripting and cross-site forgery?

The primary distinguishing feature between cross-site scripting and cross-site DDos forgery is that CSRF takes place under authenticated sessions when the server trusts the user, while XSS (cross-site scripting) doesn’t need permission for initiating a session that can be exploited when the vulnerable website doesn’t follow the basics to check to escape input.