CVE-2018-21153 in D7800
Summary
by MITRE
Certain NETGEAR devices are affected by a buffer overflow by an unauthenticated attacker. This affects D7800 before 1.0.1.34, DM200 before 1.0.0.50, EX2700 before 1.0.1.32, EX6100v2 before 1.0.1.70, EX6150v2 before 1.0.1.70, EX6200v2 before 1.0.1.62, EX6400 before 1.0.1.78, EX7300 before 1.0.1.62, EX8000 before 1.0.0.114, R6100 before 1.0.1.22, R7500 before 1.0.0.122, R7500v2 before 1.0.3.26, R7800 before 1.0.2.40, R8900 before 1.0.3.10, R9000 before 1.0.3.10, WN2000RPTv3 before 1.0.1.26, WN3000RPv2 before 1.0.0.56, WN3000RPv3 before 1.0.2.66, WN3100RPv2 before 1.0.0.56, WNDR4300 before 1.0.2.98, WNDR4300v2 before 1.0.0.54, WNDR4500v3 before 1.0.0.54, and WNR2000v5 before 1.0.0.64.
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Analysis
by VulDB Data Team • 06/03/2024
This vulnerability represents a critical buffer overflow condition affecting multiple NETGEAR wireless routers and access points, specifically targeting devices running firmware versions prior to the listed patches. The flaw exists within the web interface handling of HTTP requests, where input validation is insufficient to prevent excessive data from being copied into fixed-length buffers. This allows an unauthenticated remote attacker to exploit the vulnerability without requiring any credentials or prior access to the device. The affected models span several product lines including the D7800, EX series, R series, and various other NETGEAR router models, indicating a widespread issue across the vendor's product portfolio. The vulnerability is classified under CWE-121 as a stack-based buffer overflow, which is a well-documented weakness in software development practices where insufficient bounds checking permits memory corruption.
The technical exploitation of this vulnerability occurs when an attacker sends a specially crafted HTTP request to the device's web management interface. The malformed request contains data exceeding the allocated buffer space, causing a stack overflow that can overwrite adjacent memory locations. This memory corruption can potentially lead to arbitrary code execution, allowing the attacker to gain full control over the affected device. The attack vector is particularly concerning because it requires no authentication, making it accessible to anyone on the network or even remotely if the device has exposed management interfaces. The vulnerability affects devices that may be located in residential or business environments, potentially compromising entire network infrastructures.
The operational impact of this vulnerability extends beyond individual device compromise to potentially affect network security posture and organizational infrastructure. When an attacker successfully exploits this vulnerability, they can gain complete administrative control over the affected router, enabling them to modify network settings, redirect traffic, install malware, or establish persistent backdoors. This compromise can lead to man-in-the-middle attacks, DNS hijacking, or the use of the device as a pivot point for further attacks within the network. The widespread nature of affected models means that organizations with multiple NETGEAR devices could face cascading security failures, especially in environments where these devices are used as primary network gateways. The vulnerability's classification under attack techniques such as T1071.004 (Application Layer Protocol: DNS) and T1059.001 (Command and Scripting Interpreter: PowerShell) highlights the potential for further exploitation once initial access is gained.
Mitigation strategies should focus on immediate firmware updates from NETGEAR to address the buffer overflow vulnerability, as the vendor has released patches for all affected models. Network segmentation and firewall rules should be implemented to restrict access to device management interfaces, particularly if they are exposed to external networks. Regular security assessments should include inventory tracking of all network devices to identify potentially vulnerable equipment. Network monitoring solutions should be configured to detect unusual traffic patterns that might indicate exploitation attempts. Additionally, implementing network access control measures and disabling unnecessary services can reduce the attack surface for these vulnerable devices. The vulnerability demonstrates the importance of maintaining up-to-date firmware across all network infrastructure components and highlights the need for robust security practices in embedded device management. Organizations should also consider implementing network behavior analysis tools to detect anomalous patterns that might indicate exploitation of similar buffer overflow vulnerabilities in other network components.