Horizon Alert
Summary of the vulnerability and why it matters
A critical vulnerability in the Authorizer authentication and authorization server could allow unauthenticated attackers to redirect users to malicious sites, potentially leading to compromised credentials or tokens. This issue arises from improper validation of redirect URIs within the `/authorize` endpoint. While a partial fix was previously applied, the affected endpoint remained vulnerable until version 2.2.1. The main concern is confirming relevance and exposure.
- Open redirect vulnerability in authentication server.
- Affects user authentication and token handling.
- Confirm relevance and exposure to your systems.
Attack Path
How an attacker could exploit the issue
An attacker can leverage this vulnerability by first obtaining a valid `client_id` from a publicly accessible endpoint. They can then craft a malicious URL that includes this `client_id` and a specially chosen `redirect_uri`. When a user clicks this malicious link, the vulnerable server will redirect them to the attacker's chosen URL, potentially exposing sensitive tokens.
- Requires a valid client ID.
- Triggers via a crafted redirect URL.
- Risk of sensitive token exposure.
Live Threat
Current exploitation, exposure, and threat context
When supported by the advisory, this vulnerability could allow an unauthenticated attacker to trick users into a redirect, potentially exposing sensitive tokens in the URL.
- Sensitive tokens could be exposed.
- Users could be redirected to malicious sites.
- Token leakage to an attacker.
Operational Fix
Recommended remediation, mitigation, and detection steps
Application owners and platform teams are likely responsible for addressing this vulnerability in the Authorizer service. The first practical step is to identify all deployments of Authorizer, confirm their reachability and business criticality, and then assign ownership for remediation planning.
- Identify and confirm Authorizer deployments.
- Verify exposure and business impact.
- Plan vendor coordination or upgrade.
