CVE-2018-21185 in D6100
Summary
by MITRE
Certain NETGEAR devices are affected by a stack-based buffer overflow by an authenticated user. This affects D6100 before 1.0.0.57, D7800 before 1.0.1.34, R7500 before 1.0.0.122, R7500v2 before 1.0.3.24, R7800 before 1.0.2.40, R9000 before 1.0.2.52, WNDR3700v4 before 1.0.2.92, WNDR4300 before 1.0.2.94, WNDR4300v2 before 1.0.0.50, WNDR4500v3 before 1.0.0.50, and WNR2000v5 before 1.0.0.62.
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Analysis
by VulDB Data Team • 06/03/2024
This vulnerability represents a critical stack-based buffer overflow flaw that affects multiple NETGEAR router models, specifically targeting devices with firmware versions prior to the listed patches. The vulnerability is particularly concerning because it requires only authenticated access to exploit, meaning an attacker who has already gained administrative credentials or can obtain them through social engineering or other means can leverage this weakness to execute arbitrary code on the affected devices. The affected models span several popular router series including the D6100, D7800, R7500, R7500v2, R7800, R9000, WNDR3700v4, WNDR4300, WNDR4300v2, WNDR4500v3, and WNR2000v5, indicating a widespread impact across NETGEAR's product portfolio. This vulnerability falls under CWE-121 Stack-based Buffer Overflow, which is classified as a fundamental memory safety issue that can lead to complete system compromise when exploited properly.
The technical implementation of this buffer overflow occurs within the device's web interface or management protocols, where user-supplied input is processed without adequate bounds checking. When an authenticated user submits malicious input to specific parameters within the device's configuration interface, the system fails to validate input length and subsequently overflows the allocated stack buffer. This overflow can overwrite adjacent memory locations including return addresses, function pointers, and other critical control data structures, allowing an attacker with authentication access to potentially redirect execution flow to malicious code. The vulnerability exists in the device's handling of user-controllable parameters, which are typically processed during configuration changes or administrative operations through the web-based management interface. This type of vulnerability is particularly dangerous in network infrastructure devices because it can provide a persistent foothold for attackers to maintain access and potentially escalate privileges within the network.
The operational impact of this vulnerability extends beyond simple code execution, as it can enable attackers to gain complete control over the affected network devices. Once exploited, an attacker can manipulate network traffic, redirect DNS requests, install backdoors, or use the compromised device as a pivot point to attack other systems within the local network. The authenticated nature of the exploit means that an attacker who has already gained administrative credentials or can obtain them through other means can use this vulnerability to escalate their privileges or maintain persistent access to the network. This vulnerability also represents a significant risk to enterprise networks where these devices may be used as core infrastructure components, potentially allowing attackers to gain unauthorized access to critical network resources. The impact is particularly severe because the affected devices are commonly deployed in home and small office environments where network monitoring may be limited, making detection of such attacks more difficult.
Mitigation strategies for this vulnerability should focus on immediate firmware updates from NETGEAR, which address the buffer overflow through proper input validation and bounds checking mechanisms. Organizations should also implement network segmentation to limit the potential impact of compromise, ensuring that even if a device is compromised, the attacker's access is restricted to a limited portion of the network. Network monitoring should be enhanced to detect unusual traffic patterns or configuration changes that might indicate exploitation attempts. Additionally, implementing strict access controls and regular credential rotation can help reduce the risk of unauthorized access to administrative interfaces. Security professionals should also consider conducting vulnerability assessments to identify all affected devices within their network infrastructure and prioritize remediation efforts based on the criticality of the devices and their role in the network. The vulnerability demonstrates the importance of secure coding practices and regular security testing of network infrastructure devices, as it represents a failure to implement proper input validation in a critical system component. This case also highlights the need for organizations to maintain up-to-date firmware management processes and to regularly review security advisories from vendors to ensure timely patch deployment across all network infrastructure components.