Cross-Site Request Forgery

Definition of Cross-Site Request Forgery

Cross-site request forgery (CSRF) is a type of security vulnerability that occurs when an attacker tricks a user into performing unwanted actions on a web application without their knowledge. It exploits the user’s trust in a legitimate site by sending unauthorized commands from a malicious site. This can lead to unauthorized data access, account manipulation, or unintended changes in the targeted web application.


The phonetic pronunciation of “Cross-Site Request Forgery” is:KROS – SAHYT – ri-KWEST – FAWR-juh-reeHere’s a breakdown of each word:1. Cross: KROS2. Site: SAHYT3. Request: ri-KWEST4. Forgery: FAWR-juh-ree

Key Takeaways

  1. Cross-Site Request Forgery (CSRF) is a type of web security vulnerability that allows an attacker to perform unwanted actions on a user’s behalf, without their consent or knowledge.
  2. CSRF attacks usually occur when an authenticated user visits a malicious site or clicks on a specially crafted link, effectively tricking the user’s browser into executing requests on the attacker’s behalf.
  3. Some common defenses against CSRF attacks include using anti-CSRF tokens, implementing SameSite cookies, and employing proper CORS policies to prevent unauthorized websites from interacting with a web application/server.

Importance of Cross-Site Request Forgery

Cross-Site Request Forgery (CSRF) is an important technology term because it refers to a type of cyber attack that exploits a user’s trust in a website, potentially causing unauthorized actions on the user’s behalf.

This security vulnerability occurs when a malicious entity tricks a user into performing actions on a targeted website unknowingly, leveraging the site’s authentication and the user’s active session.

By understanding and addressing CSRF, website developers can implement proper security measures, such as anti-CSRF tokens or same-site cookies, to protect users and maintain trust in online platforms, ultimately contributing to a safer internet environment.


Cross-Site Request Forgery, or CSRF, is a malicious practice that exploits the trust a web application has in an authenticated user’s identity. It serves the purpose of manipulating authenticated users into executing unintended actions on a web application, without their knowledge or consent.

By leveraging the user’s active session, attackers can perform unauthorized activities, such as changing account details, making transactions, or even manipulating content. This security vulnerability is commonly found in web applications and can have severe consequences if not appropriately addressed.

The primary use of CSRF attacks is to deceive a user into performing unintended actions on a web application while maintaining the guise of a legitimate request. This is typically done by embedding malicious code or URL links within emails, websites, or social media messages.

As a victim unknowingly interacts with these deceitful elements, the attacker gains the ability to execute requests on behalf of the authenticated user, thus manipulating the application’s data and outcome. To defend against CSRF threats, developers employ various protection mechanisms, such as CSRF tokens and same-origin policies, ensuring the security of both users’ sensitive data and application integrity.

Examples of Cross-Site Request Forgery

GitHub Cross-Site Request Forgery (2013): In March 2013, a security vulnerability was discovered in GitHub that involved a cross-site request forgery (CSRF) flaw. This allowed an attacker to make unauthorized and malicious changes to victim’s repository, such as modifying or deleting content, without their knowledge. GitHub quickly fixed the CSRF vulnerability by implementing an anti-CSRF token in forms and validation mechanisms to ensure that all actions were explicitly authorized by the authenticated user.

Hacking Facebook using Cross-Site Request Forgery (2008): In 2008, a CSRF vulnerability was found in Facebook that would allow an attacker to change the privacy settings of a user without their knowledge or consent. If a victim unknowingly visited a malicious website while logged into Facebook, their privacy settings could be changed in the background without their permission. This vulnerability was due to insufficient CSRF protection measures, and Facebook promptly took action to improve their protections against CSRF attacks.

Netflix Cross-Site Request Forgery Vulnerability (2010): In 2010, a researcher discovered a CSRF vulnerability on the Netflix website that allowed an attacker to manipulate a user’s account. By getting a victim to click on a malicious link, an attacker could add DVDs to their queue, change shipping addresses, or even initiate account cancellation. This occurred because Netflix failed to properly verify the origin of incoming HTTP requests. Netflix resolved this issue by implementing more rigorous CSRF protections in their request-handling processes.

FAQ: Cross-Site Request Forgery

1. What is Cross-Site Request Forgery (CSRF)?

Cross-Site Request Forgery is a type of web vulnerability that tricks users into performing unintended actions on a web application, without their consent or knowledge. It enables an attacker to force the user’s browser to send malicious requests or unauthorized actions to a website they are authenticated with.

2. How does CSRF work?

CSRF exploits the trust a website has in a user’s identity. The attacker sends a malicious request with a specific action or command and the user’s session cookie. If the user is currently authenticated with the targeted website, it will automatically process the request without verifying the user’s true intent or consent, thus executing the action intended by the attacker.

3. What are some common CSRF attack examples?

Common CSRF attack examples include changing a user’s password, transferring funds from a user’s bank account, or sharing private data without the user’s knowledge.

4. How can CSRF attacks be prevented?

There are several ways to prevent CSRF attacks, including checking the HTTP Referer header, using CSRF tokens, and employing SameSite cookies. These methods help validate the user’s intent by ensuring a request originates from a trusted source and is authorized by the user.

5. What is a CSRF token?

A CSRF token is a unique, random value assigned to each user session that helps validate the authenticity of a request. It is embedded in HTML forms and then verified upon submission. This token helps ensure that the request is genuinely from the intended user, and not from an attacker trying to forge a request.

Related Technology Terms

  • Same-Origin Policy
  • Anti-CSRF Tokens
  • Session Hijacking
  • Authentication Bypass
  • Security Headers

Sources for More Information

Technology Glossary

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