CVE-2016-5368 in AR3200
Summary
by MITRE
Memory leak in Huawei AR3200 before V200R007C00SPC900 allows remote attackers to cause a denial of service (memory consumption) via a large number of crafted Multiprotocol Label Switching (MPLS) packets.
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Analysis
by VulDB Data Team • 08/26/2022
The vulnerability identified as CVE-2016-5368 affects Huawei AR3200 routers running firmware versions prior to V200R007C00SPC900, representing a critical memory leak flaw that can be exploited remotely to trigger denial of service conditions. This issue specifically targets the Multiprotocol Label Switching protocol implementation within the router's network processing stack, where improper handling of crafted MPLS packets leads to progressive memory consumption without adequate cleanup mechanisms. The vulnerability falls under the category of memory management flaws that can be leveraged by attackers to exhaust system resources and render network services unavailable to legitimate users.
The technical root cause of this vulnerability stems from insufficient input validation and memory management within the MPLS packet processing module of the Huawei AR3200 device. When the router receives specially crafted MPLS packets containing malformed or excessively large label stacks, the system fails to properly release allocated memory resources after processing these packets. This memory leak occurs repeatedly with each malicious packet received, gradually consuming available system memory until the device becomes unresponsive or crashes entirely. The flaw demonstrates characteristics consistent with CWE-401, which describes improper handling of memory allocation and deallocation in software systems. The vulnerability can be exploited through network-based attacks without requiring authentication, making it particularly dangerous in production environments where availability of network infrastructure is critical.
From an operational impact perspective, this vulnerability creates significant risk for network availability and business continuity, particularly in enterprise and service provider environments where Huawei AR3200 devices serve as core routing infrastructure. The memory consumption pattern can be sustained over time, allowing attackers to maintain prolonged denial of service conditions without detection, as the memory leak may not immediately cause system failure but gradually degrades performance until complete service disruption occurs. Network administrators may observe increasing memory usage patterns, system slowdowns, and intermittent connectivity issues that could be misdiagnosed as other network problems. The attack vector allows for remote exploitation from any location on the network, making it difficult to defend against through traditional network segmentation approaches. This vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks, and represents a classic example of how protocol implementation flaws can be weaponized to compromise system availability.
Mitigation strategies for CVE-2016-5368 should prioritize immediate firmware upgrades to Huawei V200R007C00SPC900 or later versions that contain the necessary patches to address the memory leak in MPLS packet handling. Network administrators should implement rate limiting and packet filtering rules at network boundaries to restrict the volume of MPLS traffic that can reach affected devices, particularly when dealing with untrusted network segments. Monitoring systems should be configured to detect unusual memory consumption patterns and trigger alerts when memory usage exceeds predefined thresholds, enabling proactive response to potential exploitation attempts. Network segmentation and access control measures should be strengthened to limit exposure of affected devices to unnecessary MPLS traffic. Additionally, implementing intrusion detection systems capable of identifying malformed MPLS packets can provide early warning of exploitation attempts, while regular security assessments of network infrastructure should include verification of firmware versions and patch status to prevent similar vulnerabilities from persisting in the network ecosystem.