CVE-2017-6162 in BIG-IP
Summary
by MITRE
In F5 BIG-IP LTM, AAM, AFM, Analytics, APM, ASM, DNS, Edge Gateway, GTM, Link Controller, PEM, Websafe software version 12.0.0 to 12.1.2, 11.6.0 to 11.6.1, 11.4.0 to 11.5.4, 11.2.1, in some cases TMM may crash when processing TCP traffic. This vulnerability affects TMM via a virtual server configured with TCP profile. Traffic processing is disrupted while Traffic Management Microkernel (TMM) restarts. If the affected BIG-IP system is configured to be part of a device group, it will trigger a failover to the peer device.
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Analysis
by VulDB Data Team • 01/05/2023
The vulnerability described in CVE-2017-6162 represents a critical stability issue within F5 BIG-IP systems that impacts multiple software modules including Local Traffic Manager AAM AFM Analytics APM ASM DNS Edge Gateway GTM Link Controller PEM and Websafe. This weakness specifically targets the Traffic Management Microkernel TMM component which serves as the core processing engine for TCP traffic handling in F5 appliances. The vulnerability manifests when TMM encounters TCP traffic processing scenarios involving virtual servers configured with TCP profiles, leading to system crashes that can disrupt network services and compromise availability. The affected versions span multiple release lines including 12.0.0 through 12.1.2 11.6.0 through 11.6.1 11.4.0 through 11.5.4 and 11.2.1, indicating this issue has persisted across several major releases and represents a fundamental flaw in the TCP processing logic.
The technical flaw underlying CVE-2017-6162 stems from improper handling of TCP traffic within the TMM subsystem when specific virtual server configurations are in place with TCP profiles enabled. This condition creates a scenario where the TMM process becomes unstable and terminates unexpectedly during normal traffic processing operations. The crash occurs specifically during TCP traffic analysis and routing decisions, suggesting that the vulnerability exists in the packet processing pipeline where TCP connection states are managed or where TCP profile parameters are applied to incoming traffic flows. The root cause likely involves buffer overflows memory corruption or improper state management when processing TCP packets that meet certain criteria defined by the virtual server TCP profile configuration.
The operational impact of this vulnerability extends beyond simple service disruption to encompass significant business continuity concerns for organizations relying on F5 BIG-IP appliances for critical network infrastructure. When TMM crashes, the entire virtual server configuration becomes unavailable until the system restarts and reinitializes the traffic management processes. This disruption can occur during peak traffic periods leading to service degradation or complete outages for applications and services that depend on these load balancing and traffic management capabilities. The vulnerability's potential to trigger failover operations in device group configurations compounds the impact by causing unnecessary switchover events that can lead to additional service disruption and increased operational overhead for network administrators. Network availability is severely compromised as the affected system cannot process TCP traffic until the TMM component restarts, which may take several minutes depending on the system configuration and load.
Organizations affected by CVE-2017-6162 should implement immediate mitigations including applying the latest F5 security patches and updates that address the TMM crash vulnerability. Network administrators should also consider implementing traffic filtering rules to reduce exposure while waiting for official patches, though this approach may not fully resolve the underlying issue. Monitoring systems should be enhanced to detect TMM restart events and failover operations that may indicate exploitation of this vulnerability. The vulnerability aligns with CWE-129 Input Validation and CWE-248 Unchecked Return Value categories, indicating both improper input handling and failure to properly validate system states during processing operations. From an ATT&CK perspective this vulnerability could be leveraged as part of a broader attack chain targeting availability services and may be classified under T1499 System Shutdown Reboot techniques when used to disrupt network services through intentional system crashes. Organizations should also review their device group configurations to minimize the impact of automatic failover events and ensure proper redundancy planning is in place to maintain service availability during patch deployment windows.