CVE-2018-21176 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, R6100 before 1.0.1.20, R7500 before 1.0.0.122, 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, including the D6100, R6100, R7500, R7800, R9000, WNDR3700v4, WNDR4300, WNDR4300v2, WNDR4500v3, and WNR2000v5 series. The vulnerability specifically targets authenticated users who can exploit the flaw through the device's web interface, making it particularly dangerous as it requires minimal prerequisites for exploitation. The affected firmware versions indicate that this issue has been present across multiple generations of NETGEAR routers, suggesting a systemic flaw in the software development lifecycle or code review processes. This vulnerability falls under the CWE-121 stack-based buffer overflow category, which is classified as a serious memory safety issue that can lead to arbitrary code execution.
The technical implementation of this vulnerability allows an authenticated attacker to manipulate input parameters through the web management interface, specifically targeting memory allocation on the stack where the program stores local variables and function call information. When a user submits crafted input to a vulnerable parameter, the program fails to properly validate the input length, causing data to overflow into adjacent memory locations. This overflow can overwrite critical program execution data including return addresses, function pointers, and other control structures, enabling an attacker to redirect program execution flow. The vulnerability's impact is particularly severe because it requires authentication, which means the attacker must first obtain valid credentials, but once authenticated, they can leverage this flaw to gain complete control over the device's operation. According to ATT&CK framework, this vulnerability maps to T1068 for local privilege escalation and T1059 for command execution, representing a significant threat to network infrastructure security.
The operational impact of this vulnerability extends beyond simple device compromise, as these routers serve as critical network infrastructure components that control access to entire networks. An attacker who successfully exploits this vulnerability can gain complete administrative control over the affected devices, potentially enabling them to modify network configurations, redirect traffic, install malware, or establish persistent backdoors. The widespread deployment of these affected router models across both consumer and enterprise networks creates a substantial attack surface, as many organizations may unknowingly operate vulnerable equipment. The affected devices include popular models that are commonly used in home and small office environments, making them attractive targets for cybercriminals seeking to establish footholds within networks. The vulnerability's presence in multiple firmware versions suggests that NETGEAR may have failed to implement proper input validation or memory management practices during their development process, creating a persistent security weakness that affects numerous device variants.
Mitigation strategies should focus on immediate firmware updates from NETGEAR, which would address the underlying buffer overflow issue through proper input validation and memory management. Organizations should also implement network segmentation to limit the potential impact of a successful exploitation, ensuring that compromised routers cannot easily be used as stepping stones to access other network resources. Network monitoring should be enhanced to detect unusual traffic patterns that might indicate exploitation attempts, while access controls should be strengthened to prevent unauthorized authentication. The vulnerability highlights the importance of secure coding practices and regular security assessments, particularly for network infrastructure devices that serve as critical entry points for network traffic. Additionally, implementing network access control lists and firewall rules can help limit the attack surface and reduce the likelihood of exploitation, while regular security audits should be conducted to identify similar vulnerabilities in other network equipment. Organizations should also consider implementing intrusion detection systems specifically designed to monitor for exploitation attempts targeting router firmware vulnerabilities, as these systems can provide early warning of potential attacks against network infrastructure components.