CVE-2018-21192 in D6100
Summary
by MITRE
Certain NETGEAR devices are affected by a stack-based buffer overflow by an authenticated user. This affects D6100 before 1.0.0.57, R6100 before 1.0.1.20, R7800 before 1.0.2.40, R9000 before 1.0.3.6, WNDR3700v4 before 1.0.2.92, WNDR4300 before 1.0.2.94, WNDR4300v2 before 1.0.0.50, WNDR4500v3 before 1.0.0.50, and WNR2000v5 before 1.0.0.62.
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Analysis
by VulDB Data Team • 06/03/2024
This vulnerability represents a critical stack-based buffer overflow flaw that affects multiple NETGEAR router models, specifically targeting devices in the D6100, R6100, R7800, R9000, WNDR3700v4, WNDR4300, WNDR4300v2, WNDR4500v3, and WNR2000v5 product lines. The vulnerability is particularly concerning because it requires only authenticated access to exploit, meaning an attacker who has already gained administrative credentials or can obtain them through social engineering or other means can leverage this flaw to execute arbitrary code on the affected devices. The affected firmware versions indicate that this issue spans multiple generations of NETGEAR routers, suggesting a widespread impact across the vendor's product portfolio.
The technical nature of this vulnerability stems from improper input validation within the device's web interface handling mechanisms, where user-supplied data is not adequately bounded before being copied into fixed-size stack buffers. This classic buffer overflow condition creates a scenario where an authenticated user can craft malicious input that exceeds the allocated buffer space, leading to memory corruption that can be exploited to overwrite adjacent memory locations, including return addresses and function pointers. According to CWE-121, this vulnerability falls under stack-based buffer overflow conditions where insufficient bounds checking allows attackers to write beyond the allocated buffer boundaries. The exploitation of such flaws typically enables attackers to gain full control over the device's operating system, potentially allowing for persistent backdoor access, data exfiltration, or the ability to use the compromised device as a pivot point for attacking other systems within the local network.
The operational impact of this vulnerability extends beyond simple device compromise, as these routers serve as critical network infrastructure components that often control network access, manage firewall rules, and provide essential services such as DNS resolution and DHCP management. When compromised, these devices can be used to redirect network traffic, intercept communications, or create persistent access points for further attacks. The attack surface is particularly dangerous because routers typically have elevated privileges and are often located in network perimeters where they can serve as entry points for broader network infiltration. From an ATT&CK framework perspective, this vulnerability maps to techniques such as privilege escalation and persistence, where an authenticated user can leverage the buffer overflow to gain unauthorized access to system resources and potentially establish long-term access to the network infrastructure. The affected devices also represent a significant risk to network security posture, as they can be used to conduct man-in-the-middle attacks, DNS poisoning, or other network-level attacks that compromise the integrity and confidentiality of network communications.
Mitigation strategies for this vulnerability should prioritize immediate firmware updates from NETGEAR to address the buffer overflow conditions in the affected device models. Organizations should also implement network segmentation to limit the potential impact of compromised routers and establish monitoring for unusual network traffic patterns that might indicate exploitation attempts. Network administrators should review and tighten authentication controls to minimize the risk of unauthorized access to router management interfaces, while also implementing network access control lists and firewall rules to limit the exposure of router management interfaces to only trusted network segments. The vulnerability highlights the importance of maintaining up-to-date firmware across all network infrastructure devices and implementing robust security monitoring to detect potential exploitation attempts. Additionally, organizations should consider implementing network traffic analysis tools to identify anomalous behavior that might indicate the use of this vulnerability for lateral movement or command and control communications. Given that this vulnerability affects multiple router models and firmware versions, comprehensive inventory management and patch management processes are essential to ensure all affected devices receive timely security updates and to prevent similar issues from arising in the future.