Vanus Gateway Missing Authorization Vulnerability

Executive Summary

This vulnerability in Vanus 0.8.0 through 0.9.0 is a missing authorization flaw in the gateway component. It allows any authenticated user to call restricted methods like Subscribe, Ack, and unregistered methods without proper permission checks. Attackers can hijack another tenant's subscription by supplying its ID, read and acknowledge its events, block legitimate access, and even list cluster users.

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Detection Guidance

Check Vanus gateway logs for unauthorized Subscribe, Ack, or ListUser method calls. Monitor network traffic for unexpected subscription hijacking attempts or event acknowledgments from unauthorized users. Review authentication logs for failed permission checks in gateway components.

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Impact Analysis

An attacker could intercept, read, or delete events meant for other users, disrupt services by starving legitimate consumers, or gain unauthorized access to sensitive data. They might also enumerate users in the cluster to plan further attacks.

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Compliance Impact

This vulnerability could lead to unauthorized data access or disclosure, violating GDPR's data protection principles and HIPAA's confidentiality requirements. It may result in non-compliance due to insufficient access controls and potential data breaches.

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Mitigation Strategies

Upgrade Vanus to a patched version if available. Disable or restrict access to the gateway's Subscribe, Ack, and ListUser methods. Implement strict input validation for subscription sink URLs. Enable authentication and authorization checks for all gateway operations.

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