What is an Open Redirect?
An Open Redirect occurs when a web application accepts untrusted user input (such as a URL) and redirects the user to an external website without proper validation.
Attackers can exploit this to trick users into visiting malicious sites, steal personal data, or distribute malware.
How Does it Work?
URL Parameter: A vulnerable site might accept a "redirect" parameter like this:https://example.com/redirect?url=http://victim-site.com
If the input isn’t validated, the attacker can modify the URL to redirect to any other site. For example:https://example.com/redirect?url=http://malicious-site.com
Users unknowingly click on the link, thinking it’s a legitimate redirect, but instead, they’re sent to a phishing site or a malicious page.Example Payload
https://example.com/redirect?url=http://attacker-site.comThe payload redirects users to attacker-site.com, where they could be tricked into entering their login credentials or downloading harmful files.
How to Prevent Open Redirects?
Validate URLs: Only allow redirects to trusted domains (e.g., your own site). Use Safe Redirection: Instead of passing arbitrary URLs, map user inputs to known URLs or a whitelist of safe destinations. Sanitize Input: Always sanitize user input to prevent malicious content from being executed.
Pro Tip: Always double-check redirects, especially on user-generated links, to protect your users and your site’s security!