CVE-2018-21165 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 router models including R6100, R7500, R7800, R8900, R9000, WNDR3700v4, WNDR4300, WNDR4300v2, WNDR4500v3, and WNR2000v5, all of which are susceptible to denial of service conditions. The flaw stems from inadequate input validation within the device's web management interface, specifically in how it handles HTTP requests. When an attacker sends malformed or specially crafted requests to the router's administrative web server, the device fails to properly validate the input parameters, leading to a crash or complete service interruption.
The technical implementation of this vulnerability involves the router's inability to gracefully handle malformed HTTP headers or request parameters in its web interface. This type of flaw typically falls under CWE-20, which describes "Improper Input Validation," and represents a classic example of how insufficient sanitization of user-supplied data can lead to system instability. The vulnerability allows an unauthenticated attacker to send crafted requests that cause the router's web server process to consume excessive resources or enter an invalid state, ultimately resulting in a denial of service condition that renders the device inaccessible to legitimate users.
The operational impact of this vulnerability is significant for network administrators and end users who rely on these routers for their network connectivity. Once exploited, the denial of service condition can persist until the device is manually restarted or the firmware is updated, potentially disrupting network services for extended periods. This affects not only individual users but also enterprise environments where these routers serve as critical network infrastructure components. The vulnerability particularly impacts business continuity as network administrators may lose access to router configuration interfaces during an attack, requiring physical intervention or remote access to restore services.
Mitigation strategies for this vulnerability primarily involve applying the vendor-provided firmware updates that address the input validation flaws in the affected devices. Network administrators should prioritize updating all affected NETGEAR routers to their latest firmware versions, particularly those that include patches for CVE-2018-21165. Additionally, implementing network segmentation and access control measures can help reduce the attack surface by limiting direct access to router management interfaces from external networks. The ATT&CK framework categorizes this type of vulnerability under T1190 - Exploit Public-Facing Application, highlighting the importance of securing externally accessible network services. Organizations should also consider implementing network monitoring solutions that can detect anomalous traffic patterns indicative of exploitation attempts, as well as maintaining regular inventory tracking of all network devices to ensure comprehensive vulnerability management across the entire infrastructure.