CVE-2019-6604 in BIG-IP
Summary
by MITRE
On BIG-IP 11.5.1-11.5.8, 11.6.1-11.6.3, 12.1.0-12.1.3.6, 13.0.0-13.1.1.1, and 14.0.0-14.0.0.2, under certain conditions, hardware systems with a High-Speed Bridge and using non-default Layer 2 forwarding configurations may experience a lockup of the High-Speed Bridge.
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 08/17/2023
The vulnerability described in CVE-2019-6604 affects F5 BIG-IP systems operating within specific software versions and hardware configurations, representing a critical infrastructure issue that can lead to complete system failure. This vulnerability specifically impacts devices running BIG-IP software versions 11.5.1 through 11.5.8, 11.6.1 through 11.6.3, 12.1.0 through 12.1.3.6, 13.0.0 through 13.1.1.1, and 14.0.0 through 14.0.0.2, where the hardware includes a High-Speed Bridge component. The issue manifests when these systems utilize non-default Layer 2 forwarding configurations, creating a scenario where the High-Speed Bridge component becomes unresponsive and effectively locks up the entire system.
The technical flaw stems from improper handling of packet forwarding within the High-Speed Bridge hardware component when specific Layer 2 forwarding configurations are implemented. This condition creates a deadlock scenario where the bridge component cannot process incoming packets properly, leading to complete system lockup. The vulnerability is particularly concerning because it affects the fundamental networking infrastructure component that handles high-speed packet forwarding, making it a critical point of failure for network services. The issue occurs under specific operational conditions that involve the interaction between hardware and software configuration parameters, particularly when non-standard Layer 2 forwarding rules are applied.
The operational impact of this vulnerability is severe and can result in complete service disruption for organizations relying on F5 BIG-IP systems for their network infrastructure. When the High-Speed Bridge locks up, all network traffic passing through the affected system becomes blocked, leading to widespread outages that can affect critical business operations. Organizations using these vulnerable versions may experience extended downtime while attempting to recover from the lockup condition, which often requires manual intervention and potentially system reboot procedures. The vulnerability affects both legacy and newer versions of the BIG-IP software, indicating that the underlying flaw has persisted across multiple release cycles and requires immediate attention from network administrators.
Organizations should implement immediate mitigation strategies including upgrading to patched versions of the BIG-IP software that address this specific hardware bridge locking issue. The vulnerability aligns with CWE-674, which deals with the principle of least privilege and proper error handling in system components, and can be mapped to ATT&CK technique T1499.004 which covers network denial of service attacks that target infrastructure components. System administrators should also consider implementing monitoring solutions that can detect bridge lockup conditions and automatically trigger failover mechanisms to minimize service disruption. Additionally, organizations should review their Layer 2 forwarding configurations to identify and potentially modify non-standard settings that could trigger this vulnerability, while maintaining detailed documentation of system configurations for rapid recovery procedures.