CVE-2019-20736 in D6000
Summary
by MITRE
Certain NETGEAR devices are affected by a stack-based buffer overflow by an authenticated user. This affects D6000 before 1.0.0.72, D6100 before 1.0.0.63, R7800 before 1.0.2.52, R8900 before 1.0.4.2, R9000 before 1.0.4.2, WNDR3700v4 before 1.0.2.102, WNDR4300v1 before 1.0.2.104, WNDR4300v2 before 1.0.0.58, WNDR4500v3 before 1.0.0.58, WNR2000v5 before 1.0.0.68, and XR500 before 2.3.2.32.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 05/31/2024
This vulnerability represents a critical stack-based buffer overflow flaw that affects multiple NETGEAR networking devices, creating a significant security risk for affected networks. The vulnerability is particularly concerning because it requires only authenticated access to exploit, meaning that an attacker who has gained legitimate credentials to access the device can leverage this flaw to execute arbitrary code. The affected models span several popular NETGEAR router series including the D6000, D6100, R7800, R8900, R9000, WNDR3700v4, WNDR4300v1, WNDR4300v2, WNDR4500v3, WNR2000v5, and XR500 device families. These devices are widely deployed in both residential and small business environments, amplifying the potential impact of this vulnerability.
The technical nature of this buffer overflow stems from improper input validation within the device's web interface or management software, where user-supplied data is copied to a fixed-size stack buffer without adequate bounds checking. This allows an authenticated user to overflow the buffer and potentially overwrite adjacent memory locations, including return addresses and function pointers. According to CWE-121, this classification describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite the stack and potentially execute malicious code. The vulnerability falls under the ATT&CK technique T1059.007 for Command and Scripting Interpreter, as successful exploitation would enable an attacker to execute arbitrary commands on the affected device.
The operational impact of this vulnerability extends beyond simple code execution, as it provides attackers with persistent access to network infrastructure that could be used for man-in-the-middle attacks, DNS hijacking, or as a pivot point for attacking other devices on the network. Once an attacker gains control of the router, they can modify network traffic, redirect users to malicious sites, or establish persistent backdoors that could remain undetected for extended periods. The affected firmware versions indicate that this vulnerability has existed for several years, suggesting that many organizations may be unknowingly running vulnerable equipment. Network administrators should consider this vulnerability as part of a broader attack surface that includes unpatched firmware, weak authentication mechanisms, and insufficient network segmentation.
Mitigation strategies should include immediate firmware updates from NETGEAR for all affected device models, as these updates typically contain fixes for the buffer overflow conditions. Organizations should also implement network monitoring to detect unusual traffic patterns or unauthorized access attempts to router management interfaces. The principle of least privilege should be enforced by ensuring that only authorized personnel have access to router management functions, and multi-factor authentication should be implemented where possible. Network segmentation can help limit the impact if an attacker successfully exploits this vulnerability, as it prevents lateral movement within the network. Additionally, regular vulnerability assessments and network audits should be conducted to identify and remediate similar issues in other network infrastructure components, as this vulnerability demonstrates the importance of proper input validation and memory management in embedded systems.