CVE-2018-21207 in D3600
Summary
by MITRE
Certain NETGEAR devices are affected by a stack-based buffer overflow by an unauthenticated attacker. This affects D3600 before 1.0.0.67, D6000 before 1.0.0.67, D7800 before 1.0.1.30, EX2700 before 1.0.1.28, R6100 before 1.0.1.20, R7500 before 1.0.0.118, R7500v2 before 1.0.3.24, R7800 before 1.0.2.40, R9000 before 1.0.2.52, WN2000RPTv3 before 1.0.1.20, WN3000RPv3 before 1.0.2.50, WN3100RPv2 before 1.0.0.56, WNDR3700v4 before 1.0.2.96, WNDR4300 before 1.0.2.98, WNDR4300v2 before 1.0.0.50, and WNDR4500v3 before 1.0.0.50.
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Analysis
by VulDB Data Team • 06/03/2024
This vulnerability represents a critical stack-based buffer overflow condition affecting multiple NETGEAR router models, specifically those listed in the affected versions. The flaw exists within the device's web interface handling of incoming HTTP requests, where insufficient input validation allows an attacker to craft malicious payloads that exceed the allocated buffer space on the stack. This type of vulnerability falls under the common weakness enumeration CWE-121, which specifically addresses stack-based buffer overflow conditions that occur when data is copied into a fixed-length buffer without proper bounds checking.
The technical implementation of this vulnerability allows an unauthenticated attacker to exploit the buffer overflow by sending specially crafted HTTP requests to the affected devices. When the router processes these malformed requests, the excessive data overflows into adjacent memory locations on the stack, potentially corrupting critical program execution flow. This condition creates an opportunity for arbitrary code execution or complete system compromise, as the attacker can manipulate the instruction pointer to redirect program execution to malicious code injected into the overflowed buffer space.
The operational impact of this vulnerability extends beyond simple network disruption, as it provides attackers with persistent access to network infrastructure without requiring any authentication credentials. This makes the attack surface particularly dangerous for enterprise environments where these devices may serve as primary network gateways or access points. The vulnerability affects a wide range of consumer and small office networking equipment, indicating a systemic issue in the firmware development practices across multiple device generations. The specific affected models span several years of production, suggesting that this was likely a long-standing issue that was not properly addressed during the development lifecycle.
Network security professionals should immediately implement mitigation strategies including firmware updates from NETGEAR, network segmentation to limit access to affected devices, and monitoring for suspicious HTTP traffic patterns. The ATT&CK framework categorizes this vulnerability under T1210 - Exploitation of Remote Services, as it represents an exploitation of a remote service vulnerability in network infrastructure devices. Additionally, this vulnerability demonstrates the importance of input validation and memory safety practices in embedded systems development, as highlighted by CWE-122 which addresses heap-based buffer overflows and similar memory corruption vulnerabilities that can lead to system compromise. Organizations should also consider implementing network access controls and firewall rules to restrict access to administrative interfaces of affected devices until proper patches are deployed.