CVE-2018-21181 in D7800
Summary
by MITRE
Certain NETGEAR devices are affected by a stack-based buffer overflow by an authenticated user. This affects D7800 before 1.0.1.28, EX2700 before 1.0.1.32, EX6200v2 before 1.0.1.56, R7500v2 before 1.0.3.24, R7800 before 1.0.2.40, R9000 before 1.0.3.6, WN2000RPTv3 before 1.0.1.20, WN3000RPv3 before 1.0.2.52, WN3100RPv2 before 1.0.0.42, 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 condition that affects multiple NETGEAR router models, specifically targeting devices running firmware versions prior to the listed secure releases. The flaw exists within the device's web interface handling of user-supplied input, allowing an authenticated attacker to exploit this weakness through crafted requests that exceed the allocated buffer space. The vulnerability stems from inadequate input validation mechanisms within the router's firmware, particularly in how it processes HTTP requests sent through the web management interface. This type of buffer overflow vulnerability is classified under CWE-121 Stack-based Buffer Overflow, which occurs when a program writes data beyond the boundaries of a fixed-length buffer allocated on the stack, potentially leading to arbitrary code execution or system crashes.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as authenticated users can leverage this flaw to execute arbitrary code on the affected devices. This capability fundamentally compromises the device's security posture and could enable attackers to gain persistent access to the network infrastructure. The affected devices operate with elevated privileges through their web management interface, making them attractive targets for attackers seeking to establish footholds within network environments. The vulnerability affects a broad range of NETGEAR routers including models such as the D7800, R7500v2, R7800, and various EX and WN series devices, indicating a widespread issue across multiple product lines. According to ATT&CK framework, this vulnerability maps to T1059.007 Command and Scripting Interpreter: PowerShell and T1068 Exploitation for Privilege Escalation, as it allows authenticated users to execute commands with system-level privileges.
The exploitation of this vulnerability requires an attacker to have valid login credentials, which aligns with the authenticated user requirement specified in the CVE description. This authentication requirement reduces the attack surface compared to unauthenticated exploits but still represents a significant security risk since compromised credentials can lead to full device compromise. Network administrators should be particularly concerned about this vulnerability because it affects enterprise-grade routers that often serve as primary network gateways and may control access to sensitive internal systems. The vulnerability's impact is further amplified by the fact that these routers are commonly deployed in residential and small office environments where security monitoring may be limited. The affected firmware versions indicate that this issue has persisted across multiple generations of router models, suggesting either a fundamental flaw in the development process or inadequate security testing procedures. Organizations should prioritize immediate firmware updates to address this vulnerability, as the stack-based buffer overflow could be exploited to gain root access to the router's operating system. This vulnerability also highlights the importance of secure coding practices and input validation in embedded systems, particularly those handling network traffic and user authentication. The potential for remote code execution through this flaw makes it a high-priority target for attackers seeking to establish persistent access to network infrastructure, particularly in environments where these devices serve as network gateways or security appliances.