CVE-2018-21222 in D3600
Summary
by MITRE
Certain NETGEAR devices are affected by a 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, R6100 before 1.0.1.20, R7500 before 1.0.0.118, R7500v2 before 1.0.3.24, R9000 before 1.0.2.52, WNDR3700v4 before 1.0.2.96, WNDR4300 before 1.0.2.98, WNDR4300v2 before 1.0.0.50, WNDR4500v3 before 1.0.0.50, and WNR2000v5 before 1.0.0.62.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 06/04/2024
This vulnerability represents a critical buffer overflow condition that affects multiple NETGEAR router models, creating a significant security risk for network infrastructure. The flaw exists within the web management interface of affected devices and allows unauthenticated attackers to exploit the buffer overflow through specially crafted HTTP requests. The vulnerability stems from inadequate input validation mechanisms within the device's firmware, specifically in how it processes HTTP headers and parameters sent to the web server component. This type of vulnerability falls under CWE-121, which describes buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The affected devices include a broad range of consumer and small business routers, with specific firmware versions identified as vulnerable across multiple product lines including the D3600, D6000, D7800, and various R-series and WNDR-series models.
The technical exploitation of this vulnerability enables attackers to execute arbitrary code on the affected devices with the privileges of the web server process, typically running as root or with administrative privileges. This occurs because the buffer overflow allows attackers to overwrite critical memory locations including return addresses and function pointers, potentially enabling code execution or system crashes. The attack vector requires no authentication, making it particularly dangerous as it can be exploited remotely by anyone with network access to the device. The vulnerability affects devices running firmware versions prior to the specified patches, with each model having its own version threshold for vulnerability. This unauthenticated remote code execution capability provides attackers with complete control over the affected devices, potentially allowing them to modify network configurations, redirect traffic, or establish persistent access points within the network.
The operational impact of this vulnerability extends beyond individual device compromise to affect entire network infrastructures, as routers serve as critical network gateways and security boundaries. When exploited, the vulnerability can lead to complete network takeover, enabling attackers to perform man-in-the-middle attacks, redirect DNS traffic, or establish backdoors for continued access. The affected devices typically operate in residential and small business environments where network security awareness may be limited, increasing the potential for widespread exploitation. According to ATT&CK framework, this vulnerability maps to T1059.007 for remote code execution and T1071.001 for application layer protocol usage. The attack surface is further expanded by the fact that these routers often serve as the primary network entry point for home and small office networks, making them attractive targets for attackers seeking persistent access to larger networks.
Mitigation strategies for this vulnerability should focus on immediate firmware updates from NETGEAR, which address the buffer overflow through proper input validation and memory management. Network administrators should implement network segmentation to isolate affected devices from critical systems, while monitoring for unusual network traffic patterns that might indicate exploitation attempts. Additional protective measures include disabling unnecessary services, implementing firewall rules to restrict access to the web management interface, and conducting regular vulnerability assessments of network infrastructure. The vulnerability also highlights the importance of firmware security practices and the need for manufacturers to implement robust input validation mechanisms. Organizations should also consider network monitoring solutions that can detect anomalous behavior patterns consistent with exploitation attempts, particularly focusing on unusual HTTP request patterns that might indicate buffer overflow exploitation attempts.