CVE-2013-4632 in Access Router
Summary
by MITRE
The Huawei Access Router (AR) before V200R002SPC003 allows remote attackers to cause a denial of service (device reset) via a crafted field in a DHCP request, as demonstrated by a request from an IP phone.
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Analysis
by VulDB Data Team • 05/05/2018
The vulnerability identified as CVE-2013-4632 affects Huawei Access Router models operating on firmware versions prior to V200R002SPC003, representing a critical security flaw that enables remote attackers to induce device reset conditions through maliciously crafted DHCP requests. This vulnerability specifically targets the router's handling of DHCP protocol messages, particularly those originating from IP phones or similar network devices that utilize DHCP for network configuration. The flaw demonstrates how network infrastructure devices can be compromised through manipulation of standard network protocols, highlighting the importance of robust input validation in embedded systems. The attack vector involves sending a specially crafted DHCP request containing malformed fields that trigger an unexpected behavior in the router's DHCP processing module, ultimately resulting in a complete device reboot.
The technical implementation of this vulnerability stems from inadequate input validation within the router's DHCP server implementation, which fails to properly sanitize or validate incoming DHCP request fields before processing them. When the router receives a malformed DHCP request containing crafted field values, the parsing logic encounters unexpected data structures that cause the device to crash or reset. This behavior aligns with CWE-129, Input Validation, and CWE-248, Uncaught Exception, as the system does not properly handle malformed input data. The vulnerability specifically manifests when the router's DHCP processing module attempts to parse and store the malicious field values, leading to memory corruption or execution flow disruption that results in the device reboot. The attack requires minimal privileges and can be executed remotely, making it particularly dangerous as it allows unauthorized parties to disrupt network services without physical access to the device.
The operational impact of this vulnerability extends beyond simple service disruption to potentially create significant network reliability issues for organizations relying on Huawei routers for network infrastructure. When exploited, the device reset can interrupt network connectivity for all connected devices, including critical business systems, VoIP phones, and other network-dependent services. The vulnerability affects enterprise networks where IP phones are commonly used, as these devices frequently initiate DHCP requests during normal operation, providing attackers with legitimate opportunities to trigger the exploit. From an attacker perspective, this vulnerability maps to ATT&CK technique T1499.004, Network Denial of Service, and T1595.001, Network Infrastructure Manipulation, as it enables the attacker to compromise network infrastructure and disrupt service availability. The device reset can occur repeatedly, potentially leading to persistent network outages that require manual intervention to restore normal operation.
Organizations should implement immediate mitigation strategies including firmware updates to V200R002SPC003 or later versions that contain the necessary patches addressing the DHCP parsing vulnerability. Network administrators should also consider implementing DHCP filtering mechanisms and access control lists to limit the sources of DHCP requests that can reach the vulnerable routers. Monitoring network traffic for anomalous DHCP request patterns can help detect potential exploitation attempts, while implementing network segmentation can limit the impact of successful attacks. The vulnerability demonstrates the critical importance of maintaining up-to-date network infrastructure firmware and implementing proper security monitoring procedures. Additional mitigations include configuring routers to disable unnecessary DHCP services when not required, implementing network access controls to restrict DHCP request sources, and establishing regular security assessments to identify similar vulnerabilities in network infrastructure devices. The incident highlights the need for comprehensive vulnerability management programs that include regular firmware updates, security assessments, and incident response procedures to address similar threats in network infrastructure components.