CVE-2016-8797 in S6700
Summary
by MITRE
Huawei AR3200 with software V200R007C00, V200R005C32, V200R005C20; S12700 with software V200R008C00, V200R007C00; S5300 with software V200R008C00, V200R007C00, V200R006C00; S5700 with software V200R008C00, V200R007C00, V200R006C00; S6300 with software V200R008C00, V200R007C00; S6700 with software V200R008C00, V200R007C00; S7700 with software V200R008C00, V200R007C00, V200R006C00; S9300 with software V200R008C00, V200R007C00, V200R006C00; and S9700 with software V200R008C00, V200R007C00, V200R006C00 allow remote attackers to send abnormal Multiprotocol Label Switching (MPLS) packets to cause memory exhaustion.
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Analysis
by VulDB Data Team • 11/24/2022
This vulnerability affects Huawei networking equipment including ar3200, s12700, s5300, s5700, s6300, s6700, s7700, s9300, and s9700 series switches and routers. The flaw resides in the MPLS packet processing functionality where remote attackers can exploit a memory exhaustion condition by sending malformed or abnormal MPLS packets to the affected devices. This represents a classic denial of service vulnerability that can be triggered without authentication, making it particularly dangerous in network environments where such devices are exposed to untrusted traffic. The vulnerability stems from insufficient input validation and memory management within the MPLS processing module, allowing attackers to consume system resources rapidly through crafted packet sequences. The affected software versions span multiple generations of Huawei's networking software, indicating a widespread issue that affects various device families across different product lines. According to CWE classification, this vulnerability maps to CWE-122, which describes heap-based buffer overflow conditions that can lead to memory corruption and system instability. The ATT&CK framework categorizes this as a denial of service attack technique under the T1499.004 sub-technique, specifically targeting network infrastructure devices to disrupt service availability.
The technical implementation of this vulnerability involves the improper handling of MPLS packet headers during the packet processing lifecycle. When the affected devices receive specially crafted MPLS packets, the system fails to properly validate the packet structure or limit memory allocation for processing these packets. This leads to uncontrolled memory consumption as the system attempts to process malformed packets, eventually exhausting available memory resources and causing the device to become unresponsive or crash entirely. The memory exhaustion occurs at the kernel level within the MPLS packet processing module, where insufficient bounds checking allows arbitrary memory allocation based on packet fields that should be strictly validated. Attackers can leverage this vulnerability to perform sustained denial of service attacks against network infrastructure, potentially disrupting critical network services and causing significant operational downtime for enterprises relying on these devices. The impact is particularly severe because MPLS is commonly used in enterprise and service provider networks for traffic engineering and quality of service implementations, making the compromise of such devices a serious security concern.
The operational impact of this vulnerability extends beyond simple service disruption to potentially compromise entire network segments. When affected devices become unresponsive due to memory exhaustion, network traffic may be rerouted through alternate paths or completely blocked, depending on the network topology and redundancy mechanisms in place. This can lead to cascading failures in larger network infrastructures where multiple devices rely on MPLS for proper routing and traffic management. Organizations may experience extended downtime, loss of network visibility, and potential data transmission failures that can affect business operations and customer service delivery. The vulnerability's remote exploitability means that attackers can initiate attacks from outside the network perimeter, making it particularly dangerous for devices that are exposed to public networks or have insufficient network segmentation controls. Additionally, the widespread nature of affected device models means that large enterprise networks or service provider infrastructures may be impacted by a single vulnerability affecting multiple device types across different product lines.
Mitigation strategies for this vulnerability should include immediate software updates from Huawei addressing the memory handling issues in MPLS packet processing. Network administrators should implement access control lists to filter MPLS traffic at network boundaries and restrict MPLS packet processing to trusted sources only. The implementation of rate limiting and traffic monitoring mechanisms can help detect abnormal packet patterns that may indicate exploitation attempts. Organizations should also consider deploying network segmentation strategies to isolate critical devices and limit the potential impact of successful attacks. Regular security assessments and vulnerability scanning should be conducted to identify any remaining instances of affected software versions. According to industry best practices for network security, implementing network intrusion detection systems can help identify exploitation attempts by monitoring for unusual packet patterns and memory usage anomalies. The vulnerability highlights the importance of proper input validation and memory management in network infrastructure software, emphasizing the need for rigorous security testing and code review processes during software development. Organizations should also maintain detailed incident response procedures for dealing with denial of service attacks targeting network infrastructure devices to minimize operational impact when such vulnerabilities are exploited.