Cross-site request forgery

Definition

Cross-site request forgery (CSRF) is a type of attack that tricks a user into performing actions on a web application without their consent, exploiting the trust that a site has in the user's browser. In these attacks, malicious requests are sent on behalf of an authenticated user, potentially leading to unauthorized actions such as changing account settings or making transactions. Understanding CSRF is essential for securing web applications against such vulnerabilities.

5 Must Know Facts For Your Next Test

1. CSRF attacks rely on the user's authenticated session with a website, making them particularly dangerous when users are logged in.
2. To prevent CSRF attacks, developers can implement anti-CSRF tokens, which must be included in requests and verified by the server.
3. CSRF can affect any web application that relies on cookies for authentication and does not adequately verify the source of incoming requests.
4. Phishing techniques are often employed in conjunction with CSRF, tricking users into clicking links that trigger malicious actions.
5. Common targets of CSRF attacks include online banking sites, social media platforms, and any application where users can perform sensitive actions.

Review Questions

• How does a CSRF attack exploit the trust between a user and a web application?
  • A CSRF attack takes advantage of the trust that a web application has in the user's browser by sending unauthorized requests as if they were legitimate actions initiated by the user. When a user is authenticated and logged into a site, their browser automatically includes cookies in any requests made to that site. If a malicious site tricks the user into performing an action, such as clicking a link, the request is executed with the user's credentials, potentially leading to harmful outcomes.
• What strategies can developers implement to mitigate CSRF vulnerabilities in web applications?
  • Developers can use several strategies to mitigate CSRF vulnerabilities, including implementing CSRF tokens that are unique for each session or request. These tokens must be submitted alongside any form submission or state-changing request and verified by the server. Additionally, using the Same-Origin Policy can help limit how documents or scripts from one origin interact with resources from another, reducing the risk of CSRF attacks. It's also important for developers to educate users about not clicking on suspicious links or buttons.
• Evaluate the implications of CSRF vulnerabilities for both users and web application providers and suggest best practices for handling such risks.
  • CSRF vulnerabilities can lead to significant risks for both users and web application providers, including unauthorized actions taken on behalf of users and potential financial loss or data exposure. For users, this could mean unwanted transactions or changes to their accounts without their knowledge. Web application providers must adopt best practices such as implementing anti-CSRF tokens, regularly updating security protocols, and educating users about safe browsing habits. By prioritizing security measures and maintaining open communication with users about potential threats, providers can build trust and protect sensitive information.

Related terms

Same-Origin Policy: A security measure that restricts how documents or scripts loaded from one origin can interact with resources from another origin.

CSRF Token: A unique, secret, and unpredictable value generated by the server and included in forms submitted by users to verify the authenticity of requests.

XSS (Cross-Site Scripting): A security vulnerability that allows attackers to inject malicious scripts into web pages viewed by other users, often used in conjunction with CSRF attacks.