CVE-2018-21212 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, D6100 before 1.0.0.56, 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 • 06/04/2024
This vulnerability represents a critical buffer overflow condition affecting multiple NETGEAR wireless routers and networking devices, as identified by CVE-2018-21212. The flaw exists within the web interface handling of these devices, allowing unauthenticated attackers to exploit the vulnerability without requiring any credentials or prior access to the network. The affected models span several generations of NETGEAR's consumer and enterprise networking equipment, with specific firmware versions indicating the scope of impacted devices. This type of vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions, and represents a fundamental security weakness in memory management practices within the device's web server implementation. The buffer overflow occurs when processing user-supplied input through HTTP requests, particularly in parameters related to device configuration and management functions.
The technical exploitation of this vulnerability enables remote code execution capabilities, as attackers can overwrite memory contents and potentially inject malicious code into the device's operating system. The vulnerability manifests when the device processes specially crafted HTTP requests containing overly long input strings that exceed the allocated buffer space, leading to memory corruption and potential system compromise. This type of attack vector aligns with ATT&CK technique T1210, which involves exploiting weaknesses in remote services to gain system access. The attack surface is particularly concerning given that these devices are typically deployed in home and small office environments where network security measures may be minimal, and the devices are often accessible from the internet without proper firewall protection. Network traffic analysis reveals that the vulnerable devices typically listen on standard HTTP ports, making them susceptible to automated scanning and exploitation attempts.
The operational impact of this vulnerability extends beyond simple device compromise, as affected routers could be used as entry points for broader network attacks or to facilitate persistent access to victim networks. Once compromised, these devices could be used to redirect traffic, monitor network communications, or serve as launch points for attacks against other devices within the local network. The vulnerability affects a broad range of NETGEAR models, suggesting a systemic issue in the firmware development process rather than isolated incidents, indicating potential design flaws in the web server implementation across multiple device generations. Security researchers have documented that the affected devices typically run embedded Linux systems with standard web server implementations that fail to properly validate input lengths, creating a consistent exploitation pattern across the entire vulnerable product line. The lack of authentication requirements makes this vulnerability particularly dangerous as it can be exploited by anyone with access to the internet, regardless of their relationship to the network owner.
Mitigation strategies for this vulnerability require immediate firmware updates from NETGEAR, as the company has released patches addressing the buffer overflow condition. Network administrators should implement network segmentation to isolate affected devices from critical infrastructure, while also deploying intrusion detection systems to monitor for exploitation attempts. The recommended approach includes disabling unnecessary services and ports, implementing proper firewall rules, and conducting thorough network scanning to identify potentially compromised devices. Security professionals should also consider implementing network monitoring solutions that can detect anomalous traffic patterns consistent with exploitation attempts. Organizations should prioritize updating all affected devices to the latest firmware versions, as the patches typically include input validation improvements and memory management fixes that address the root cause of the vulnerability. Additionally, network administrators should conduct regular security assessments to ensure that all devices within their environment are running patched firmware versions, as many organizations may not be aware of the presence of these vulnerable devices on their networks. The vulnerability serves as a reminder of the critical importance of secure coding practices and regular security updates for network infrastructure devices, particularly those with direct internet exposure.