Horizon Alert
Summary of the vulnerability and why it matters
This advisory concerns a vulnerability in a payment integration plugin that processes transactions for events. The issue could allow an attacker to redirect requests to a malicious server, potentially exposing sensitive access tokens used to communicate with payment providers. The primary concern is to confirm if this specific plugin is in use and identify any potential exposure.
- Plugin may leak payment access tokens.
- Critical to verify if this specific plugin is in use.
- Confirm relevance and exposure of payment integration.
Attack Path
How an attacker could exploit the issue
An attacker can exploit this vulnerability by manipulating the redirection URL after a payment attempt. The pretix-oppwa plugin improperly concatenates a user-supplied `resourcePath` with a base URL without proper validation, allowing an attacker to craft a malicious URL that points to a different server. This could lead to the exposure of sensitive access tokens, granting unauthorized access to the payment provider's system.
- Attacker crafts a malicious redirect URL.
- Plugin concatenates attacker input to base URL.
- Sensitive access tokens are leaked.
Live Threat
Current exploitation, exposure, and threat context
This vulnerability could allow an attacker to trick the payment integration into sending sensitive payment provider access tokens to an attacker-controlled server. This could occur when a user completes a payment and is redirected back to the pretix system, provided the attacker can manipulate the redirect URL.
- Payment provider access tokens at risk.
- Insecure URL concatenation.
- Sensitive data leakage.
Operational Fix
Recommended remediation, mitigation, and detection steps
The payment integration plugin for pretix likely falls under the responsibility of the application or platform team managing the pretix instance. The initial step involves identifying all pretix deployments, confirming their internet reachability and business criticality, and then assigning ownership for remediation. Coordination with the payment provider for new access tokens is also a necessary post-update action.
- Application or platform team owns remediation.
- Verify internet-facing pretix instances are identified.
- Coordinate with payment provider for new tokens.
