CVE-2021-38525 in D3600
Summary
by MITRE • 08/11/2021
Certain NETGEAR devices are affected by a stack-based buffer overflow by an authenticated user. This affects D3600 before 1.0.0.76, D6000 before 1.0.0.76, D6200 before 1.1.00.36, D7000 before 1.0.1.70, EX6200v2 before 1.0.1.78, EX7000 before 1.0.1.78, EX8000 before 1.0.1.186, JR6150 before 1.0.1.18, PR2000 before 1.0.0.28, R6020 before 1.0.0.42, R6050 before 1.0.1.18, R6080 before 1.0.0.42, R6120 before 1.0.0.46, R6220 before 1.1.0.80, R6260 before 1.1.0.64, R6300v2 before 1.0.4.34, R6700 before 1.0.2.6, R6700v2 before 1.2.0.36, R6800 before 1.2.0.36, R6900 before 1.0.2.4, R6900P before 1.3.1.64, R6900v2 before 1.2.0.36, R7000 before 1.0.9.42, R7000P before 1.3.1.64, R7800 before 1.0.2.60, R8900 before 1.0.4.12, R9000 before 1.0.4.12, and XR500 before 2.3.2.40.
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Analysis
by VulDB Data Team • 08/16/2021
This vulnerability represents a critical stack-based buffer overflow flaw in NETGEAR networking equipment that enables authenticated users to potentially execute arbitrary code on affected devices. The vulnerability resides in the web management interface of multiple router models and is classified as a buffer overflow due to improper input validation during parameter processing. Attackers who have gained legitimate credentials can exploit this weakness to overwrite adjacent memory locations on the device's stack, potentially leading to complete system compromise. The affected devices span across various NETGEAR router series including D3600, D6000, R6020, R6050, R6080, and numerous other models, with specific firmware version thresholds indicating the vulnerability's presence before certain security patches were implemented. This type of vulnerability directly maps to CWE-121 Stack-based Buffer Overflow, which is categorized under the CWE Top 25 Most Dangerous Software Weaknesses and represents a fundamental memory safety issue that has been a persistent concern in embedded systems and network devices.
The operational impact of this vulnerability extends beyond simple privilege escalation as it provides attackers with the capability to execute arbitrary code with the privileges of the web server process. This means that an authenticated attacker could potentially gain full control over the affected router, enabling them to modify network configurations, redirect traffic, install malware, or establish persistent backdoors. The attack requires only valid user credentials, which are often easily obtained through social engineering, default credential exploitation, or other initial compromise techniques. Once exploited, the vulnerability could allow attackers to manipulate network traffic, create man-in-the-middle attacks, or use the compromised device as a pivot point for further attacks within the local network. The vulnerability's presence in multiple device models suggests a widespread issue affecting NETGEAR's product line, indicating either a common codebase or shared implementation flaws across different router architectures. This aligns with ATT&CK technique T1059.007 Command and Scripting Interpreter: Unix Shell, as attackers could leverage the compromised device to execute commands and maintain persistence.
Mitigation strategies for this vulnerability should focus on immediate firmware updates from NETGEAR, as the company has released patches addressing this specific buffer overflow issue. Network administrators should also implement strict access controls and monitor for unauthorized access attempts to router management interfaces. The principle of least privilege should be enforced by limiting administrative access to only necessary personnel and implementing multi-factor authentication where possible. Network segmentation and monitoring of router traffic can help detect anomalous behavior that might indicate exploitation attempts. Additionally, organizations should consider implementing network access control lists and disabling unnecessary services on affected devices. Security teams should monitor for indicators of compromise such as unusual network traffic patterns, unauthorized configuration changes, or attempts to access the web management interface from unexpected locations. Regular vulnerability assessments and penetration testing should be conducted to identify similar issues in other network infrastructure components, as this vulnerability demonstrates the importance of proper input validation in embedded systems and web interfaces. The vulnerability also highlights the need for robust security testing during development cycles, particularly for firmware components that handle user input through web interfaces, as the stack-based buffer overflow could have been prevented through proper bounds checking and input validation mechanisms.