CVE-2016-9252 in BIG-IP
Summary
by MITRE
The Traffic Management Microkernel (TMM) in F5 BIG-IP before 11.5.4 HF3, 11.6.x before 11.6.1 HF2 and 12.x before 12.1.2 does not properly handle minimum path MTU options for IPv6, which allows remote attackers to cause a denial-of-service (DoS) through unspecified vectors.
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Analysis
by VulDB Data Team • 09/17/2024
The vulnerability identified as CVE-2016-9252 affects the Traffic Management Microkernel (TMM) component within F5 BIG-IP appliances, representing a critical denial-of-service weakness that impacts multiple version streams of the popular network traffic management platform. This flaw specifically manifests in the improper handling of minimum path MTU (Maximum Transmission Unit) options for IPv6 protocol traffic, creating exploitable conditions that can be leveraged by remote attackers to disrupt service availability. The affected versions include F5 BIG-IP 11.5.4 prior to HF3, 11.6.x versions before HF2, and 12.x versions before 12.1.2, indicating a widespread impact across several major release lines of the platform.
The technical root cause of this vulnerability lies in the TMM's insufficient processing of IPv6 minimum path MTU options, which are critical parameters used to determine the largest packet size that can be transmitted over a network path without fragmentation. When the TMM encounters IPv6 packets with specific MTU configuration parameters, it fails to properly validate or handle these options, leading to potential system instability or complete service disruption. This improper handling creates a condition where maliciously crafted IPv6 traffic can trigger memory corruption or resource exhaustion within the TMM process, ultimately resulting in the appliance becoming unresponsive or requiring manual intervention to restore normal operations.
The operational impact of this vulnerability extends beyond simple service disruption, as it can affect critical network infrastructure components that rely on F5 BIG-IP appliances for load balancing, traffic management, and application delivery services. Remote attackers can exploit this weakness without requiring authentication credentials, making it particularly dangerous in environments where network exposure is high. The unspecified vectors mentioned in the description suggest that multiple attack scenarios may be possible, potentially including crafted packet sequences, specific IPv6 header configurations, or manipulation of MTU negotiation processes that could trigger the vulnerable code path within the TMM. This vulnerability directly relates to CWE-122, which addresses buffer overflow conditions, and represents a classic example of improper input validation in network protocol handling.
Organizations utilizing F5 BIG-IP appliances must prioritize immediate remediation through the application of available patches and hotfixes provided by F5, specifically targeting the affected version ranges mentioned in the CVE description. The recommended mitigation strategy involves upgrading to the patched versions 11.5.4 HF3, 11.6.1 HF2, or 12.1.2, respectively, depending on the current appliance version. Network administrators should also implement monitoring solutions to detect potential exploitation attempts and establish incident response procedures to address any DoS events that may occur. From an ATT&CK framework perspective, this vulnerability aligns with the T1499.004 technique related to network denial of service and represents a critical weakness that could be leveraged as part of broader attack campaigns targeting network infrastructure. The vulnerability demonstrates the importance of proper protocol implementation and validation in security-critical network components, as highlighted in industry best practices for secure network device development and the NIST Cybersecurity Framework's risk management guidelines.