CVE-2017-6151 in BIG-IP
Summary
by MITRE
In F5 BIG-IP LTM, AAM, AFM, Analytics, APM, ASM, DNS, Edge Gateway, GTM, Link Controller, PEM, WebAccelerator and WebSafe software version 13.0.0, undisclosed requests made to BIG-IP virtual servers which make use of the "HTTP/2 profile" may result in a disruption of service to TMM.
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Analysis
by VulDB Data Team • 01/18/2023
The vulnerability identified as CVE-2017-6151 represents a significant denial of service weakness affecting F5 BIG-IP appliances across multiple modules including Local Traffic Manager AAM AFM Analytics APM ASM DNS Edge Gateway GTM Link Controller PEM and WebAccelerator. This flaw specifically manifests when the BIG-IP system processes undisclosed requests directed at virtual servers utilizing the HTTP/2 profile configuration. The vulnerability falls under the category of service disruption rather than direct exploitation allowing attackers to potentially bring down critical network services through carefully crafted requests. The affected software versions encompass the 13.0.0 release across all listed modules, indicating a widespread impact throughout the F5 BIG-IP platform ecosystem. This vulnerability directly relates to CWE-400 which describes unspecified denial of service conditions in network services and aligns with ATT&CK technique T1499.1 which covers network denial of service attacks targeting infrastructure components.
The technical mechanism behind this vulnerability involves the processing of HTTP/2 requests within the Traffic Management Microkernel TMM component of the BIG-IP system. When virtual servers configured with HTTP/2 profiles receive malformed or unexpected requests, the system experiences instability that leads to service disruption. The HTTP/2 protocol implementation in these F5 appliances contains a flaw in request parsing or connection handling that causes the TMM process to become unresponsive or crash. This disruption affects the core traffic management functionality and can result in complete service outages for applications and services relying on the affected BIG-IP virtual servers. The vulnerability is particularly concerning because HTTP/2 is increasingly adopted in modern web applications due to its performance benefits and the fact that it is enabled by default in many configurations.
The operational impact of CVE-2017-6151 extends beyond simple service interruption to potentially compromise business continuity and network availability. Organizations relying on F5 BIG-IP appliances for critical infrastructure may experience significant downtime when this vulnerability is exploited, especially in high-traffic environments where HTTP/2 connections are prevalent. The disruption affects the entire TMM subsystem which handles all traffic processing for the virtual servers, making this a critical issue for enterprises depending on F5 load balancing and application delivery services. Network administrators may observe connection timeouts, application unavailability, and overall system instability across multiple services simultaneously. The vulnerability also impacts the broader security posture of affected organizations as service disruption can mask other attacks or prevent proper incident response activities from functioning correctly.
Mitigation strategies for CVE-2017-6151 require immediate attention from security teams and system administrators responsible for F5 BIG-IP deployments. The primary recommendation involves applying the official F5 security patches released to address this specific vulnerability in the 13.0.0 software version. Organizations should also consider implementing temporary workarounds such as disabling HTTP/2 profiles on affected virtual servers until proper patches can be deployed. Network segmentation and monitoring solutions should be enhanced to detect unusual traffic patterns that may indicate exploitation attempts. Additionally, system administrators should implement comprehensive logging and alerting mechanisms to quickly identify when TMM processes become unresponsive or when service disruptions occur. The vulnerability demonstrates the importance of maintaining up-to-date security patches and implementing proper change management processes to ensure timely deployment of critical security updates across enterprise infrastructure components.