CVE-2018-21215 in D3600
Summary
by MITRE
Certain NETGEAR devices are affected by a buffer overflow by an unauthenticated attacker. This affects D3600 before 1.0.0.67, D6000 before 1.0.0.67, D6100 before 1.0.0.56, EX2700 before 1.0.1.28, R7500v2 before 1.0.3.24, R9000 before 1.0.2.52, WN2000RPTv3 before 1.0.1.20, WN3000RPv3 before 1.0.2.50, and WN3100RPv2 before 1.0.0.56.
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Analysis
by VulDB Data Team • 06/04/2024
This vulnerability represents a critical buffer overflow condition that affects multiple NETGEAR wireless routers and networking devices, creating a significant security risk for affected networks. The flaw exists in the web-based management interface of these devices, where an unauthenticated attacker can exploit the vulnerability without requiring any credentials or prior access to the network. The affected models span several device families including the D3600, D6000, D6100, EX2700, R7500v2, R9000, WN2000RPTv3, WN3000RPv3, and WN3100RPv2 series, all of which are vulnerable due to improper input validation in their web server implementations. The vulnerability is classified as a buffer overflow according to CWE-121, which occurs when a program writes data beyond the boundaries of a fixed-length buffer, potentially overwriting adjacent memory locations. This type of vulnerability falls under the ATT&CK technique T1210 - Exploitation of Remote Services, as it allows attackers to remotely execute code on affected devices through network-based attacks.
The technical implementation of this vulnerability stems from insufficient bounds checking in the device's web server handling of HTTP requests, particularly in parameters related to configuration and system management functions. When an attacker sends a specially crafted HTTP request containing excessive data to specific endpoints, the application fails to validate the input length before copying it into a fixed-size buffer. This allows the attacker to overwrite adjacent memory locations, potentially including return addresses, function pointers, or other critical control data. The buffer overflow can be triggered through various HTTP methods including GET and POST requests, making it particularly dangerous as it can be exploited through simple web-based attacks. The vulnerability is particularly concerning because it affects devices that are typically deployed in home and small office environments where network monitoring is limited, and users may not regularly update firmware.
The operational impact of this vulnerability extends beyond simple device compromise, as affected devices can be fully controlled by remote attackers who exploit the buffer overflow. Successful exploitation allows an attacker to execute arbitrary code with the privileges of the web server process, typically running with elevated system privileges. This can lead to complete device takeover, enabling attackers to modify network configurations, redirect traffic, install malicious firmware, or use the device as a pivot point for attacking other systems within the local network. The vulnerability also poses risks to data privacy and network integrity, as attackers can potentially access sensitive information stored on the devices or use them to launch further attacks against connected systems. Network administrators may face challenges in detecting exploitation attempts since the attacks can be performed entirely through standard HTTP traffic without requiring authentication or specialized tools.
Mitigation strategies for this vulnerability require immediate firmware updates from NETGEAR, as the company has released patched versions for all affected models. Organizations should prioritize updating their NETGEAR devices to the latest firmware versions that address the buffer overflow condition, with particular attention to the specific version numbers mentioned in the vulnerability description. Network segmentation and access controls should be implemented to limit exposure of these devices to untrusted networks, while monitoring for unusual HTTP traffic patterns or attempts to access management interfaces. Security professionals should also consider implementing network-based intrusion detection systems to identify potential exploitation attempts, as the attack vectors are typically visible through standard network traffic analysis. Additionally, organizations should perform regular vulnerability assessments to identify other potentially affected devices within their network infrastructure, as similar vulnerabilities may exist in other networking equipment from the same vendor or similar manufacturers. The vulnerability demonstrates the importance of proper input validation and memory management practices in embedded network devices, highlighting the need for comprehensive security testing of firmware components before deployment in production environments.