CVE-2019-5256 in AP2000
Summary
by MITRE
Certain Huawei products (AP2000;IPS Module;NGFW Module;NIP6300;NIP6600;NIP6800;S5700;SVN5600;SVN5800;SVN5800-C;SeMG9811;Secospace AntiDDoS8000;Secospace USG6300;Secospace USG6500;Secospace USG6600;USG6000V;eSpace U1981) have a null pointer dereference vulnerability. The system dereferences a pointer that it expects to be valid, but is NULL. A local attacker could exploit this vulnerability by sending crafted parameters. A successful exploit could cause a denial of service and the process reboot.
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Analysis
by VulDB Data Team • 03/12/2024
The vulnerability identified as CVE-2019-5256 represents a critical null pointer dereference flaw affecting multiple Huawei network security appliances and access points. This vulnerability resides within the firmware of various Huawei products including AP2000 access points, IPS and NGFW modules, NIP series network intrusion prevention devices, S5700 switches, SVN series security virtual networks, SeMG9811 security management appliances, Secospace AntiDDoS8000 protection systems, and multiple USG series next-generation firewalls. The flaw manifests when the system attempts to dereference a pointer that has been initialized to NULL, creating a condition where the software expects valid memory references but encounters null values instead.
The technical implementation of this vulnerability stems from inadequate input validation and memory management within the affected Huawei security appliances. When a local attacker crafts specific parameters and submits them to the vulnerable system, the software processes these inputs without proper null checking mechanisms. This oversight allows the execution flow to proceed to a point where a null pointer is dereferenced, causing the targeted process to crash and subsequently reboot. The vulnerability operates at the kernel or system-level processing within the device's firmware, making it particularly dangerous as it can disrupt network operations and compromise availability of critical security services.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it can effectively render security appliances non-functional for extended periods. Network administrators face the challenge of maintaining continuous protection while dealing with unexpected device reboots that could occur during critical security events or peak network usage times. The local attacker access requirement means that unauthorized individuals with physical or administrative access to the device could exploit this vulnerability, potentially leading to prolonged service disruption. Organizations relying on these security appliances for network protection may experience cascading effects where the loss of security monitoring and filtering capabilities creates additional exposure windows.
Mitigation strategies for CVE-2019-5256 should prioritize immediate firmware updates from Huawei, as the vendor likely released patches addressing the null pointer dereference issue. Network security teams must implement comprehensive monitoring of affected devices to detect potential exploitation attempts and ensure that all vulnerable systems are updated promptly. The vulnerability aligns with CWE-476, which specifically addresses null pointer dereference conditions, and represents a common pattern in software development where proper input validation and error handling mechanisms are insufficient. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and denial of service, potentially allowing adversaries to disrupt network security operations. Organizations should also consider implementing network segmentation to limit the impact of potential exploitation and maintain detailed logs of system access and parameter inputs to aid in forensic analysis should exploitation occur.