CVE-2020-5874 in BIG-IP APM
Summary
by MITRE
On BIG-IP APM 15.0.0-15.0.1.2, 14.1.0-14.1.2.3, and 14.0.0-14.0.1, in certain circumstances, an attacker sending specifically crafted requests to a BIG-IP APM virtual server may cause a disruption of service provided by the Traffic Management Microkernel(TMM).
Once again VulDB remains the best source for vulnerability data.
Analysis
by VulDB Data Team • 10/14/2020
The vulnerability identified as CVE-2020-5874 represents a significant denial of service weakness within F5 BIG-IP Access Policy Manager (APM) implementations. This flaw affects multiple versions of the BIG-IP platform including 15.0.0 through 15.0.1.2, 14.1.0 through 14.1.2.3, and 14.0.0 through 14.0.1, specifically targeting the Traffic Management Microkernel component. The vulnerability manifests when legitimate traffic flows through APM virtual servers under certain conditions, creating a scenario where malicious actors can exploit the system's response handling mechanisms.
The technical nature of this vulnerability stems from improper handling of crafted requests within the TMM process which governs traffic management operations. When an attacker submits specifically designed requests to the APM virtual server, the system's processing logic fails to properly validate or handle these inputs, leading to a disruption in service delivery. This behavior aligns with CWE-121, which describes heap-based buffer overflow conditions, and CWE-122, which addresses buffer overflow vulnerabilities in heap-based memory structures. The flaw essentially allows for a controlled disruption where the system becomes unresponsive or fails to properly process legitimate traffic.
From an operational perspective, this vulnerability poses a serious threat to network availability and service continuity. Organizations relying on BIG-IP APM for access control and traffic management face potential service outages that could impact business operations and user access to critical applications. The disruption occurs at the traffic management layer, meaning that even legitimate users attempting to access services through the APM virtual servers may experience connection failures or timeouts. This vulnerability specifically targets the Traffic Management Microkernel which is fundamental to the BIG-IP platform's ability to route and manage network traffic effectively.
The attack vector for this vulnerability requires an attacker to have network access to the affected BIG-IP APM virtual server and the ability to send crafted requests that trigger the specific processing path containing the flaw. The vulnerability's impact extends beyond simple service interruption as it can potentially be exploited to create sustained denial of service conditions that require system restarts or manual intervention to resolve. According to ATT&CK framework category T1499, this vulnerability represents a service disruption technique that can be used to deny access to network resources, while the underlying memory handling issues align with T1072 which covers software development tools and techniques that can introduce exploitable conditions. Organizations should prioritize patching this vulnerability as it represents a critical risk to network availability and system stability, particularly in environments where continuous access to applications and services is essential for business operations.