Open Redirect
MediumOpen Redirect
Definition
Open Redirect is a vulnerability that occurs when a web application redirects users to a URL supplied through a parameter without proper validation. Attackers exploit it to send victims to phishing sites using a seemingly legitimate link from the trusted domain.
Impact
Sophisticated phishing using the legitimate domain as the initial linkOAuth token theft when chained with authentication flowsSSRF filter bypass through a redirectMalware distribution from seemingly legitimate links
Examples
Basic Open Redirect
The application accepts any URL in the redirect parameter without checking that it belongs to the same domain. The attacker leverages this to send users to a phishing site that mimics the original page.
# Legitimate login URL with a redirect parameter https://example.com/login?redirect=/dashboard # Malicious URL that redirects to a phishing site https://example.com/login?redirect=https://evil.com/fake-login # Common validation bypasses: ?redirect=//evil.com ?redirect=https://example.com.evil.com ?redirect=https://example.com@evil.com ?redirect=/\evil.com