CVE-2021-38516 in D6220
Summary
by MITRE • 08/11/2021
Certain NETGEAR devices are affected by lack of access control at the function level. This affects D6220 before 1.0.0.48, D6400 before 1.0.0.82, D7000v2 before 1.0.0.52, D7800 before 1.0.1.44, D8500 before 1.0.3.43, DC112A before 1.0.0.40, DGN2200v4 before 1.0.0.108, RBK50 before 2.3.0.32, RBR50 before 2.3.0.32, RBS50 before 2.3.0.32, RBK20 before 2.3.0.28, RBR20 before 2.3.0.28, RBS20 before 2.3.0.28, RBK40 before 2.3.0.28, RBR40 before 2.3.0.28, RBS40 before 2.3.0.28, R6020 before 1.0.0.34, R6080 before 1.0.0.34, R6120 before 1.0.0.44, R6220 before 1.1.0.80, R6230 before 1.1.0.80, R6250 before 1.0.4.34, R6260 before 1.1.0.40, R6850 before 1.1.0.40, R6350 before 1.1.0.40, R6400v2 before 1.0.2.62, R6700v3 before 1.0.2.62, R6700v2 before 1.2.0.36, R6800 before 1.2.0.36, R6900v2 before 1.2.0.36, R7000 before 1.0.9.34, R6900P before 1.3.1.44, R7000P before 1.3.1.44, R7100LG before 1.0.0.48, R7200 before 1.2.0.48, R7350 before 1.2.0.48, R7400 before 1.2.0.48, R7450 before 1.2.0.36, AC2100 before 1.2.0.36, AC2400 before 1.2.0.36, AC2600 before 1.2.0.36, R7500v2 before 1.0.3.38, R7800 before 1.0.2.58, R7900 before 1.0.3.8, R7960P before 1.4.1.44, R8000 before 1.0.4.28, R7900P before 1.4.1.30, R8000P before 1.4.1.30, R8900 before 1.0.4.2, R9000 before 1.0.4.2, RAX120 before 1.0.0.74, RBK752 before 3.2.16.6, RBR750 before 3.2.16.6, RBS750 before 3.2.16.6, RBK852 before 3.2.16.6, RBR850 before 3.2.16.6, RBS850 before 3.2.16.6, WNR3500Lv2 before 1.2.0.56, XR450 before 2.3.2.32, and XR500 before 2.3.2.32.
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Analysis
by VulDB Data Team • 08/16/2021
The vulnerability identified as CVE-2021-38516 represents a critical access control flaw affecting numerous NETGEAR networking devices across multiple product lines and firmware versions. This weakness stems from insufficient authorization checks at the function level within the device's web interface, allowing unauthorized users to bypass normal access restrictions and gain elevated privileges. The affected devices span across various router models including the D6220, D6400, D7000v2, and numerous R-series routers, with firmware versions ranging from early releases to more recent iterations that have not yet been patched. The vulnerability specifically targets the authentication and authorization mechanisms that should normally prevent unauthorized access to administrative functions, creating a pathway for attackers to execute commands with elevated privileges.
From a technical perspective, this flaw manifests as a lack of proper input validation and access control enforcement within the device's web application layer. When users attempt to access administrative functions through the web interface, the system fails to properly verify whether the requesting user possesses sufficient privileges to perform the requested operations. This weakness falls under the CWE-285 category of Improper Authorization, which specifically addresses scenarios where systems fail to properly enforce access controls. The vulnerability allows attackers to potentially access sensitive administrative functions that should be restricted to authorized users only, including configuration changes, firmware updates, and network management operations. The impact is particularly severe because it enables attackers to gain complete control over the affected devices without proper authentication.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it creates opportunities for attackers to compromise entire network infrastructures through these vulnerable devices. Once an attacker gains access to an affected router, they can manipulate network configurations, redirect traffic, install malicious firmware, or use the device as a pivot point for attacking other systems within the network. This aligns with ATT&CK technique T1071.004 for Application Layer Protocol: DNS, where compromised network devices can be leveraged for further attacks. The widespread nature of affected devices means that organizations with multiple NETGEAR routers are at risk, potentially creating extensive attack surfaces that can be exploited for network infiltration or lateral movement.
Mitigation strategies for CVE-2021-38516 should focus on immediate firmware updates provided by NETGEAR, as these patches address the underlying access control implementation flaws. Organizations must conduct comprehensive inventory assessments to identify all affected devices and prioritize remediation efforts based on network criticality and exposure. Network segmentation should be implemented to limit the potential impact of compromised devices, while monitoring systems should be deployed to detect unauthorized access attempts or configuration changes. Additionally, implementing strong network access controls, disabling unnecessary services, and enforcing robust authentication mechanisms can help reduce the attack surface. The vulnerability demonstrates the critical importance of proper access control implementation in network infrastructure devices, as highlighted in industry standards such as NIST SP 800-53 and ISO 27001, which emphasize the need for robust authorization controls in network security architectures.