Open Redirect
What are open redirects?
Open redirect is a web application vulnerability that occurs when an application uses unvalidated user input as part of a redirect URL.
An attacker can exploit this vulnerability by manipulating the input to redirect a victim to a malicious site. The impact of this vulnerability can range from phishing attacks to theft of sensitive information.
Check out this video for a high-level explanation:
What is the impact of open redirects?
An open redirect vulnerability can allow an attacker to:
- Conduct phishing attacks: An attacker can trick a victim into clicking a link that appears to be legitimate but actually redirects them to a malicious website where their sensitive information can be compromised.
- Steal sensitive information: An attacker can craft a URL that appears to be legitimate but redirects to a site that steals the victim's sensitive information, such as login credentials or credit card information.
- Distribute malware: An attacker can use an open redirect to send victims to a site that distributes malware, allowing them to gain control of the victim's device.
How to prevent open redirects?
To prevent improper open redirect vulnerabilities, it is important to implement secure coding practices, including:
- Validate redirect URLs: Ensure that all redirect URLs are validated and verified before being used in the application. This can include ensuring that the redirect URL is within the same domain as the current page or using an allow list of permitted domains.
- Avoid using untrusted input: Avoid using untrusted user input as part of a redirect URL. Use a standard URL-building function instead, which allows you to control the parameters used in the redirect URL.
- Implement security headers: Implement security headers such as Content-Security-Policy (CSP) and X-Frame-Options to help prevent open redirect attacks.
- Use secure coding practices: Use secure coding practices to prevent open redirect vulnerabilities. This includes input validation, output encoding, and regular security audits.