CVE-2018-21142 in R6100
Summary
by MITRE
Certain NETGEAR devices are affected by denial of service. This affects R6100 before 1.0.1.22, R7500 before 1.0.0.122, R7800 before 1.0.2.42, R8900 before 1.0.3.10, R9000 before 1.0.3.10, WNDR3700v4 before 1.0.2.96, WNDR4300 before 1.0.2.98, WNDR4300v2 before 1.0.0.54, WNDR4500v3 before 1.0.0.54, and WNR2000v5 before 1.0.0.64.
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Analysis
by VulDB Data Team • 06/02/2024
This vulnerability affects multiple NETGEAR wireless routers and access points, specifically targeting devices in the R6100, R7500, R7800, R8900, R9000, WNDR3700v4, WNDR4300, WNDR4300v2, WNDR4500v3, and WNR2000v5 product lines. The issue manifests as a denial of service condition that can render these networking devices inoperable, effectively cutting off network connectivity for users within the affected network segments. These devices are commonly deployed in residential and small office environments where reliable network access is critical for daily operations.
The technical flaw stems from improper input validation within the device's web management interface or firmware processing mechanisms. When subjected to malformed or specially crafted requests, the affected devices fail to properly handle the input, leading to system instability or complete system crash. This vulnerability allows remote attackers to exploit the flaw without requiring authentication, making it particularly dangerous as it can be triggered from external networks. The root cause aligns with CWE-20, which describes improper input validation, and represents a classic example of a buffer overflow or input handling error that can be leveraged for denial of service attacks.
The operational impact of this vulnerability extends beyond simple network disruption, as it can affect business continuity and user productivity in environments where these devices serve as primary network infrastructure. Organizations relying on these routers may experience unexpected downtime, potentially affecting critical services, remote work capabilities, and communication systems. The vulnerability's remote exploitability means that attackers can initiate the denial of service condition from anywhere on the internet, without requiring physical access to the device or local network presence. This characteristic places the vulnerability within the ATT&CK framework's T1499.004 technique for Network Denial of Service, which specifically addresses attacks targeting network infrastructure.
Network administrators should prioritize immediate remediation of affected devices through firmware updates provided by NETGEAR, as these updates typically contain patches that address the underlying input validation flaws. The vulnerability affects multiple generations of NETGEAR devices, indicating a systemic issue within the firmware development process that may require broader security assessments of the affected product lines. Organizations should also implement network monitoring to detect unusual traffic patterns or device behavior that might indicate exploitation attempts. Additionally, network segmentation strategies can help limit the impact of potential exploitation by isolating affected devices from critical network segments, thereby reducing the attack surface and minimizing business disruption potential.
The vulnerability demonstrates the importance of robust input validation and proper error handling in embedded network devices, particularly those with web interfaces that are accessible from external networks. It highlights the need for comprehensive security testing of firmware components and the implementation of defense-in-depth strategies for network infrastructure devices. Given the widespread deployment of these affected models, this vulnerability represents a significant risk to network availability and underscores the critical importance of maintaining current firmware versions for all network equipment.