CVE-2020-5872 in BIG-IP
Summary
by MITRE
On BIG-IP 14.1.0-14.1.2.3, 14.0.0-14.0.1, 13.1.0-13.1.3.1, and 12.1.0-12.1.4.1, when processing TLS traffic with hardware cryptographic acceleration enabled on platforms with Intel QAT hardware, the Traffic Management Microkernel (TMM) may stop responding and cause a failover event.
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Analysis
by VulDB Data Team • 10/14/2020
The vulnerability identified as CVE-2020-5872 represents a critical reliability issue within F5 Networks BIG-IP systems that affects multiple software versions including 14.1.x series through 14.1.2.3, 14.0.x series through 14.0.1, 13.1.x series through 13.1.3.1, and 12.1.x series through 12.1.4.1. This flaw specifically manifests when the system processes TLS traffic with hardware cryptographic acceleration enabled, particularly on platforms equipped with Intel Quick Assist Technology QAT hardware accelerators. The Traffic Management Microkernel (TMM) component, which serves as the core processing engine for traffic handling in BIG-IP systems, experiences a condition that leads to system unresponsiveness and subsequent failover events.
The technical nature of this vulnerability stems from improper handling of cryptographic operations within the TMM when utilizing hardware acceleration features. The flaw occurs during TLS traffic processing where the system's cryptographic operations, typically offloaded to the Intel QAT hardware, trigger a condition that causes the TMM to become unresponsive. This behavior constitutes a denial of service scenario that can lead to complete system failure and automatic failover to redundant systems. The issue is particularly concerning because it affects the fundamental traffic processing capabilities of the BIG-IP appliance, potentially disrupting critical network services and causing service interruptions across enterprise networks that rely on F5 load balancing and application delivery services.
From an operational impact perspective, this vulnerability creates significant risk for organizations deploying F5 BIG-IP systems with hardware acceleration enabled, particularly in high-availability configurations where failover events can result in service disruption and potential data loss. The vulnerability's occurrence during normal TLS traffic processing means that even routine network operations can trigger the problematic behavior, making it difficult to predict or prevent. The failover events that result from this condition can cause cascading effects throughout network infrastructure, especially in environments where multiple BIG-IP appliances are configured in active-standby or active-active configurations. Organizations may experience unexpected service interruptions, increased administrative overhead due to failover management, and potential security implications from service disruption during critical network operations.
Organizations affected by this vulnerability should prioritize applying the vendor-provided security patches and updates that address the TMM responsiveness issue. Mitigation strategies should include monitoring system logs for failover events and implementing proactive system maintenance routines to identify and address potential triggers. The vulnerability aligns with CWE-691, which addresses insufficient control flow management in security-critical code paths, and reflects patterns commonly associated with ATT&CK technique T1499.004, which involves network disruption through service availability attacks. Additionally, organizations should consider temporarily disabling hardware acceleration features on affected systems until permanent patches are deployed, though this may impact performance characteristics of TLS processing. Regular security assessments and vulnerability management procedures should include verification of system configurations to ensure that hardware acceleration is properly configured and monitored for potential issues related to this vulnerability.