CWE-601: URL Redirection to Untrusted Site ('Open Redirect')
Individual Definition in a New Window
URL Redirection to Untrusted Site ('Open Redirect')
Status: Draft
Weakness ID: 601 (Weakness Variant)
Description
Summary
A web application accepts a user-controlled input that
specifies a link to an external site, and uses that link in a Redirect. This
simplifies phishing attacks.
Extended Description
An http parameter may contain a URL value and could cause the web
application to redirect the request to the specified URL. By modifying the
URL value to a malicious site, an attacker may successfully launch a
phishing scam and steal user credentials. Because the server name in the
modified link is identical to the original site, phishing attempts have a
more trustworthy appearance.
Alternate Terms
Open Redirect
Cross-site Redirect
Cross-domain Redirect
Time of Introduction
Architecture and Design
Implementation
Likelihood of Exploit
Low
Detection Factors
Whether this issue poses a vulnerability will be subject to the
intended behavior of the application. For example, a search engine might
intentionally provide redirects.
Open redirect vulnerability in the software allows
remote attackers to redirect users to arbitrary web sites and conduct
phishing attacks via a URL in the proper
parameter.
An open redirect vulnerability in the search
script in the software allows remote attackers to redirect users to
arbitrary web sites and conduct phishing attacks via a URL as a parameter to
the proper function.
Potential Mitigations
Assume that all user inputs are malicious. Perform input validation of
all user requests.
Use a whitelist of approved URLs or domains to redirect to.
Provide an intermediate disclaimer page that provides the user with a
clear warning that they are leaving your site. Implement a long timeout
before the redirect occurs, or force the user to click on the
link.
Background Details
Phishing is a general term for deceptive attempts to coerce private
information from users that will be used for identity theft.
Description
Architecture and Design
