20 CSRF Interview Questions and Answers

Cross-Site Request Forgery (CSRF) is a type of web security vulnerability that can allow attackers to inject malicious code into a website. This can be done by tricking a user into clicking on a malicious link or by embedding malicious code in a webpage. If you are interviewing for a position that involves web security, it is likely that you will be asked questions about CSRF. In this article, we review some of the most common CSRF questions and how you should answer them.

CSRF Interview Questions and Answers

Here are 20 commonly asked CSRF interview questions and answers to prepare you for your interview:

1. What is CSRF?

CSRF stands for Cross-Site Request Forgery. It is a type of attack that tricks a user into performing an action on a website that they did not intend to do. For example, an attacker could send a victim a link that looks like it goes to a legitimate website, but actually goes to a malicious website that looks identical. When the victim clicks on the link, they may unknowingly perform an action on the malicious website that the attacker wanted them to do, such as buying something or changing their password. CSRF attacks are difficult to prevent because they exploit the trust that a user has in a website.

2. Can you give me some examples of how a CSRF attack might occur?

CSRF attacks can occur in a number of ways, but they all exploit the fact that a user’s browser will automatically send certain types of information to a website without the user’s knowledge or consent. For example, a CSRF attack might occur if a user is logged into a website and then visits a malicious website that contains a form that submits information to the first website. The malicious website might be able to submit information to the first website without the user’s knowledge or consent, and this could allow the attacker to perform actions on the first website on behalf of the user.

3. Where can we use CSRF tokens and why?

CSRF tokens can be used on any website that allows users to submit data. This is because CSRF tokens help to prevent cross-site request forgery attacks. By including a CSRF token with each request, you can be sure that the request is coming from the intended user and not from a malicious third party.

4. How do you check if your application is vulnerable to CSRF attacks?

There are a few different ways to check if your application is vulnerable to CSRF attacks. One way is to look at the application’s code and see if there are any places where user input is not properly validated. Another way is to try and exploit the application yourself and see if you are able to inject malicious code that is executed by the server.

5. What’s the difference between XSS and CSRF?

Cross-site scripting (XSS) is a type of security vulnerability that allows an attacker to inject malicious code into a web page. This code is then executed by the browser of any unsuspecting user who visits the page. CSRF, on the other hand, is a type of attack that tricks a user’s browser into making a request to a web application on behalf of the attacker. This request can perform any action that the user is authorized to perform, such as changing their password or making a purchase.

6. Why are anti-CSRF tokens not used in GET requests even though they’re vulnerable to CSRF?

The main reason is that GET requests should be idempotent, meaning that they can be safely repeated without changing the state of the server. If an attacker could inject a CSRF token into a GET request and cause the server to repeat the request, that would be a serious security vulnerability. For this reason, it’s generally considered best practice to only use anti-CSRF tokens in POST requests, which are not idempotent.

7. In what ways can you mitigate CSRF risks?

There are a few different ways that you can mitigate CSRF risks. One way is to ensure that all of your forms include a unique token that is tied to the user’s session. This token should be checked when the form is submitted to make sure that it is valid. Another way to mitigate CSRF risks is to only allow form submissions to come from the same origin as the page that the form is on. This can be done by checking the Origin header on the request.

8. How does an attacker perform a CSRF Session Token hijacking attack on a web app?

The attacker would need to first find a way to get a hold of a valid session token for the web app. Once they have a valid session token, they can then craft a malicious request that includes the session token and send it to the victim. If the victim is logged into the web app and has a valid session, then the malicious request will be executed as if it came from the victim. This can allow the attacker to perform actions on behalf of the victim, such as changing their password or making a purchase.

9. Is it possible to prevent CSRF using HTTP headers? If yes, then how?

Yes, it is possible to prevent CSRF using HTTP headers. One way to do this is to set the ‘X-Frame-Options’ header to ‘SAMEORIGIN’, which will prevent the page from being loaded in an iframe on another domain. Another way to prevent CSRF is to use a ‘Content-Security-Policy’ header with a value of ‘frame-ancestors ‘self”. This will also prevent the page from being loaded in an iframe on another domain.

10. Is it possible to protect against CSRF by checking the Referer header? If yes, how?

Yes, it is possible to protect against CSRF by checking the Referer header. By checking the Referer header, you can ensure that the request is coming from the same site that the user is currently on. This helps to prevent CSRF attacks, because it means that an attacker would not be able to spoof the Referer header in order to make it appear as though the request was coming from the same site.

11. What are the differences between SameSite cookies and HttpOnly cookies? Which one would you recommend for protecting against CSRF?

SameSite cookies are designed to prevent cross-site request forgery (CSRF) attacks by only allowing the cookie to be sent with requests initiated from the same site. HttpOnly cookies are designed to prevent cross-site scripting (XSS) attacks by only allowing the cookie to be accessed by the HTTP protocol. I would recommend using SameSite cookies to protect against CSRF attacks.

12. What is cross-site request forgery?

Cross-site request forgery, also known as CSRF or XSRF, is a type of attack that tricks a user into unknowingly executing an unwanted action on a website. This can be done by tricking the user into clicking on a malicious link, or by embedding malicious code into a page that the user visits. If successful, the attacker can perform actions on the website that the user is logged into, such as changing their password or making a purchase.

13. What are the common types of Cross-Site Request Forgery attacks?

There are two common types of CSRF attacks:

1. GET-based attacks: These attacks exploit the fact that browsers will automatically send GET requests for any URL that is referenced in the src attribute of an img tag. For example, an attacker could include an img tag in a malicious email that points to a URL on the victim’s bank’s website. When the email is opened, the browser will automatically send a GET request to the bank’s website, and if the victim is logged in, the attacker will be able to see the victim’s account information.

2. POST-based attacks: These attacks exploit the fact that browsers will automatically send POST requests for any URL that is referenced in the action attribute of a form tag. For example, an attacker could include a form tag in a malicious email that points to a URL on the victim’s bank’s website. When the email is opened, the browser will automatically send a POST request to the bank’s website, and if the victim is logged in, the attacker will be able to see the victim’s account information.

14. How does Cross-Site Request Forgery work?

CSRF works by taking advantage of the fact that browsers will automatically send cookies along with requests to any site. So, if a user is logged into a site, and a malicious site can get the user to visit it, then the malicious site can send a request to the first site that includes the user’s cookies. The first site will then think that the request is coming from the user, and will process it accordingly. This can be used to, for example, trick the user into buying something, or transferring money, without them realizing it.

15. What are some of the factors that make applications more susceptible to a Cross-Site Request Forgery attack?

There are a few different factors that can make an application more susceptible to a CSRF attack. One is if the application relies on cookies for authentication, as this can give an attacker the ability to hijack a user’s session. Another is if the application does not have proper CSRF protection measures in place, such as checking for a valid CSRF token on all POST requests.

16. What are the different methods available for detecting Cross-Site Request Forgery attacks?

There are a few different methods that can be used for detecting CSRF attacks. One is to check the HTTP headers for a referrer header, and if one is not present, then the request may be suspicious. Another method is to check for a unique token in the request body or headers, and if the token is not present, then the request may be suspicious. Finally, you can also check the browser cookies to see if there are any unusual values present that could indicate that the user’s session has been hijacked.

17. What are some best practices for preventing Cross-Site Request Forgery attacks?

There are a few different things that you can do in order to help prevent CSRF attacks:

– Use a unique token for each user that is difficult to guess, and check that this token is included with each request.
– Only allow requests to be made from the same origin (i.e. from the same domain and port).
– Use a security measure such as a CAPTCHA for particularly sensitive actions.

18. What are the steps involved in identifying Cross-Site Request Forgery vulnerabilities?

In order to identify Cross-Site Request Forgery vulnerabilities, you need to first understand what CSRF is and how it works. Once you have a good understanding of the attack, you can then start looking for potential vulnerabilities. To do this, you can examine the code for forms and links that are present on the website. If you see any forms or links that allow users to input data, you will need to check to see if there is any protection against CSRF attacks. If there is no protection, then the website is vulnerable to CSRF attacks.

19. Can you explain how you would configure a server to prevent Cross-Site Request Forgery?

There are a few different ways to configure a server to prevent Cross-Site Request Forgery, but one of the most common is to use a security token. This token is typically a randomly generated string of characters that is attached to each request. When the server receives a request, it checks the security token to make sure that it matches the one that was attached to the original request. If the token does not match, then the server knows that the request is not legitimate and can take appropriate action.

20. What are some real-world cases where apps have been successfully attacked using Cross-Site Request Forgery?

In 2013, a CSRF attack was used to exploit a vulnerability in the Yahoo! Mail service, allowing attackers to send emails from any Yahoo! Mail account without the user’s knowledge. In 2015, CSRF attacks were used to exploit a vulnerability in the popular social media site Tumblr, allowing attackers to post content on behalf of other users.