CodeQL documentation

Client-side URL redirect

ID: js/client-side-unvalidated-url-redirection
Kind: path-problem
Severity: error
Precision: high
Tags:
   - security
   - external/cwe/cwe-079
   - external/cwe/cwe-116
   - external/cwe/cwe-601
Query suites:
   - javascript-code-scanning.qls
   - javascript-security-extended.qls
   - javascript-security-and-quality.qls

Click to see the query in the CodeQL repository

Redirecting to a URL that is constructed from parts of the DOM that may be controlled by an attacker can facilitate phishing attacks. In these attacks, unsuspecting users can be redirected to a malicious site that looks very similar to the real site they intend to visit, but which is controlled by the attacker.

Recommendation

To guard against untrusted URL redirection, it is advisable to avoid putting user input directly into a redirect URL. Instead, maintain a list of authorized redirects on the server; then choose from that list based on the user input provided.

Example

The following example uses a regular expression to extract a query parameter from the document URL, and then uses it to construct a new URL to redirect to without any further validation. This may allow an attacker to craft a link that redirects from a trusted website to some arbitrary website of their choosing, which facilitates phishing attacks:

window.location = /.*redirect=([^&]*).*/.exec(document.location.href)[1];

References