CVE-2018-21145 in D7800
Summary
by MITRE
Certain NETGEAR devices are affected by a stack-based buffer overflow by an authenticated user. This affects D7800 before 1.0.1.34, DM200 before 1.0.0.50, 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 • 06/01/2024
This vulnerability represents a critical stack-based buffer overflow flaw that affects multiple NETGEAR router models, specifically targeting devices with firmware versions prior to the listed patches. The issue stems from insufficient input validation within the device's web interface administration functionality, allowing an authenticated user to exploit memory corruption through crafted input parameters. The vulnerability exists in the handling of user-supplied data within the device's management interface, where buffer boundaries are not properly enforced during string operations. This type of flaw falls under CWE-121 Stack-based Buffer Overflow, which is classified as a severe memory safety issue that can lead to arbitrary code execution or system crashes. The affected devices include popular router models such as the D7800, R6100, R7500, R7800, R8900, R9000, and various WNDR series devices, all of which share common firmware components that contain this memory corruption vulnerability.
The operational impact of this vulnerability extends beyond simple system instability, as it provides a pathway for authenticated attackers to gain elevated privileges and potentially execute malicious code on the affected devices. An attacker who has already gained access to the device's administrative interface can leverage this buffer overflow to overwrite critical memory locations, potentially leading to complete system compromise. The vulnerability's exploitation requires authentication, which reduces the attack surface compared to unauthenticated exploits, but still represents a significant risk to network security since local administrative access often provides extensive control over network traffic and device configuration. This aligns with ATT&CK technique T1072 Application Deployment Software, as the compromised device could be used as a pivot point for further network reconnaissance and lateral movement. The affected firmware versions indicate that this vulnerability has been present for several years, suggesting that many devices in the field may remain unpatched and vulnerable to exploitation.
Mitigation strategies for this vulnerability should focus on immediate firmware updates from NETGEAR, which are available for all affected device models and contain patches that address the buffer overflow conditions. Network administrators should also implement additional security controls including access restriction to administrative interfaces, network segmentation, and monitoring for unusual administrative activity that could indicate exploitation attempts. The vulnerability demonstrates the importance of proper input validation and memory management in embedded systems, where resource constraints often lead to security oversights. Organizations should conduct comprehensive inventory audits to identify all affected devices within their networks and prioritize patching based on risk assessment. Additionally, implementing network monitoring solutions that can detect anomalous behavior in router management interfaces may provide early warning of exploitation attempts. The vulnerability also highlights the need for robust security practices in IoT and networking equipment, as these devices often remain unpatched for extended periods and serve as critical infrastructure components that require consistent security maintenance. This case exemplifies how embedded device security vulnerabilities can persist across multiple generations of products and emphasizes the importance of continuous security assessment and patch management for network infrastructure equipment.