CVE-2018-21208 in D6100
Summary
by MITRE
Certain NETGEAR devices are affected by command injection by an unauthenticated attacker. This affects D6100 before 1.0.0.57, R6100 before 1.0.1.20, R7500v2 before 1.0.3.24, WNDR4300v2 before 1.0.0.50, and WNDR4500v3 before 1.0.0.50.
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Analysis
by VulDB Data Team • 06/04/2024
This vulnerability represents a critical command injection flaw in NETGEAR networking equipment that allows unauthenticated attackers to execute arbitrary commands on affected devices. The vulnerability stems from insufficient input validation within the web interface of multiple router models, creating an attack vector that bypasses authentication mechanisms entirely. The affected devices include various models from the D6100, R6100, R7500v2, WNDR4300v2, and WNDR4500v3 series, all of which share a common software implementation flaw that permits remote code execution without requiring valid credentials. The technical nature of this vulnerability aligns with CWE-77, which describes command injection flaws where untrusted data is directly incorporated into command execution contexts. This weakness enables attackers to manipulate device behavior through crafted input parameters that are subsequently processed by the system's command interpreter, potentially leading to complete device compromise and unauthorized network access.
The operational impact of this vulnerability extends beyond simple unauthorized access to encompass full system control capabilities. An unauthenticated attacker can leverage this flaw to gain root-level privileges on the affected devices, enabling them to modify network configurations, redirect traffic, install malicious firmware, or establish persistent backdoors. The vulnerability's presence in multiple device models suggests a systemic software flaw rather than isolated incidents, indicating that network administrators managing multiple NETGEAR devices face compounded security risks. The attack surface is particularly concerning given that these are consumer and small office networking devices that typically operate in unsecured environments, making them attractive targets for attackers seeking to establish footholds within larger networks. The lack of authentication requirements means that the vulnerability can be exploited remotely from the internet, eliminating the need for physical access or local network presence.
Network security professionals should recognize this vulnerability as a significant threat vector that aligns with ATT&CK technique T1059.001 for command and scripting interpreter, where adversaries execute code through legitimate system interfaces. The affected device models represent a substantial portion of NETGEAR's consumer and small business product line, making this vulnerability particularly widespread and impactful. Organizations should prioritize immediate mitigation efforts including firmware updates from NETGEAR, network segmentation to isolate affected devices, and monitoring for suspicious network traffic patterns that might indicate exploitation attempts. The vulnerability also highlights the importance of secure coding practices and input validation, particularly in web-based management interfaces where user-supplied data enters system execution contexts. Network defenders must implement comprehensive monitoring solutions to detect anomalous command execution patterns and establish incident response procedures specifically addressing unauthenticated remote code execution vulnerabilities in networking equipment. The remediation process requires careful consideration of device availability and the potential for update failures that could leave devices inoperable, emphasizing the need for proper change management procedures during security patching operations.