Authenticated Network Traffic Bypass in Arista EOS

Executive Summary

This vulnerability allows an authenticated user on a nearby network to bypass network authorization policies. It occurs during a brief window between completing authentication and the enforcement of access control lists (ACLs), allowing unrestricted traffic for milliseconds to seconds.

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Detection Guidance

This vulnerability involves a brief window where an authenticated supplicant bypasses network authorization policy. Detection may require monitoring network traffic during authentication phases, checking for unauthorized traffic spikes, or inspecting ACL enforcement logs. Specific commands depend on network equipment and monitoring tools.

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Impact Analysis

An attacker could exploit this to send unauthorized traffic, potentially accessing restricted network resources or performing actions outside their permissions during the brief window before ACL enforcement.

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Compliance Impact

This vulnerability may lead to unauthorized access or data exfiltration, violating confidentiality requirements in GDPR and HIPAA. Organizations could face compliance violations if sensitive data is exposed during the brief authorization gap.

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Mitigation Strategies

Immediate mitigation includes ensuring ACL enforcement occurs immediately after authentication completion. Review and tighten network authorization policies, monitor for unauthorized traffic during authentication windows, and apply vendor patches if available. Prioritize testing changes in a non-production environment first.

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