Path Traversal in gvproxy Network Forwarder

Executive Summary

This is a path traversal vulnerability in gvproxy, a network forwarder component of the gvisor-tap-vsock package. The issue occurs in the unauthenticated /services/forwarder/expose endpoint, which fails to validate the socket path provided by the caller. This allows an attacker to delete arbitrary files on the host system.

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Detection Guidance

Monitor network traffic for unauthorized access to the /services/forwarder/expose endpoint in gvproxy. Check for unusual file deletions or modifications on the host system. Review logs for requests containing path traversal sequences like '../' targeting sensitive directories.

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Impact Analysis

An attacker could exploit this to delete critical files on the host system, potentially causing data loss, system instability, or denial of service. Successful exploitation requires the attacker to already have code execution inside a guest VM or container.

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Compliance Impact

This vulnerability allows arbitrary file deletion on the host system, which could lead to unauthorized data destruction or manipulation. For GDPR, this may violate integrity and availability principles (Article 5) and risk data breach notifications (Article 33). For HIPAA, it could compromise protected health information integrity or availability under the Security Rule.

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Mitigation Strategies

Apply the latest patches or updates for gvisor-tap-vsock to fix the path validation issue. Restrict network access to the /services/forwarder/expose endpoint by implementing firewall rules or network segmentation. Disable the gvproxy service if not required.

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