CVE-2019-5285 in S Series Switch
Summary
by MITRE
Some Huawei S series switches have a DoS vulnerability. An unauthenticated remote attacker can send crafted packets to the affected device to exploit this vulnerability. Due to insufficient verification of the packets, successful exploitation may cause the device reboot and denial of service (DoS) condition. (Vulnerability ID: HWPSIRT-2019-03109)
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Analysis
by VulDB Data Team • 09/28/2023
The vulnerability identified as CVE-2019-5285 affects Huawei S series switches and represents a significant denial of service threat that can be exploited remotely without authentication. This vulnerability resides within the packet processing mechanisms of these network devices, specifically in how they handle incoming network traffic. The flaw manifests when the switch fails to properly validate incoming packets, creating an opportunity for malicious actors to craft specific packet sequences that can trigger unintended behavior in the device's network processing stack.
The technical implementation of this vulnerability stems from inadequate input validation within the switch's packet handling routines. When an attacker sends specifically crafted packets to the affected Huawei S series switches, the device's insufficient verification mechanisms allow these malformed packets to bypass normal processing checks. This weakness creates a condition where the switch's network processing units encounter unexpected packet structures that cause the device to enter an unstable state, ultimately leading to a complete system reboot. The vulnerability operates at the network protocol level, affecting the switch's ability to maintain stable connectivity and network operations.
From an operational perspective, this vulnerability presents a critical risk to network infrastructure reliability and availability. Network administrators face the potential for unannounced service disruptions that could affect multiple network segments depending on the switch's role in the network topology. The remote exploitation capability means that attackers can initiate denial of service conditions from outside the network perimeter, making this vulnerability particularly dangerous for enterprise and service provider networks. The lack of authentication requirements for exploitation further compounds the risk, as it eliminates the need for attackers to gain network access credentials before attempting to disrupt services.
The impact of successful exploitation extends beyond simple service interruption, potentially causing cascading failures in network infrastructure. When switches in critical network paths experience unexpected reboots, it can lead to network partitioning, routing disruptions, and extended service outages that may require manual intervention to restore normal operations. The vulnerability affects Huawei S series switches that are widely deployed in enterprise and service provider environments, making the potential impact substantial across multiple network architectures. Organizations should consider this vulnerability in their risk assessments and incident response planning.
Mitigation strategies for CVE-2019-5285 should include immediate firmware updates from Huawei to address the packet validation issues within the switch software. Network segmentation and access control measures can help reduce the attack surface by limiting which systems can reach the vulnerable switches. Implementing network monitoring solutions that can detect anomalous packet patterns may provide early warning of exploitation attempts. The vulnerability aligns with CWE-20, which describes improper input validation, and represents a typical example of how insufficient validation can lead to system instability and denial of service conditions. Organizations should also consider implementing network access control lists to restrict traffic to switch management interfaces and limit the potential for exploitation. The ATT&CK framework categorizes this vulnerability under the network denial of service tactic, highlighting the importance of network resilience and proper input validation in maintaining service availability.