CVE-2019-20734 in D6220
Summary
by MITRE
Certain NETGEAR devices are affected by a buffer overflow by an unauthenticated attacker. This affects D6220 before 1.0.0.40, D8500 before 1.0.3.39, EX3700 before 1.0.0.70, EX3800 before 1.0.0.70, EX6000 before 1.0.0.30, EX6100 before 1.0.2.22, EX6120 before 1.0.0.40, EX6130 before 1.0.0.22, EX6150v1 before 1.0.0.42, EX6200 before 1.0.3.88, EX7000 before 1.0.0.66, R6300v2 before 1.0.4.18, R6400 before 1.0.1.24, R6400v2 before 1.0.2.32, R6700 before 1.0.1.22, R6700v3 before 1.0.2.32, R6900 before 1.0.1.22, R7000 before 1.0.9.6, R6900P before 1.0.0.56, R7000P before 1.0.0.56, R7100LG before 1.0.0.42, R7300DST before 1.0.0.54, R7900 before 1.0.1.26, R8300 before 1.0.2.106, R8500 before 1.0.2.106, WN2500RPv2 before 1.0.1.54, and WNR3500Lv2 before 1.2.0.46.
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Analysis
by VulDB Data Team • 05/31/2024
This vulnerability represents a critical buffer overflow condition affecting multiple NETGEAR wireless routers and access points that operate on embedded systems with insufficient input validation mechanisms. The flaw exists within the device's web interface handling of user-supplied data, specifically in the processing of HTTP request parameters that are not properly bounds-checked before being copied into fixed-size memory buffers. This allows an unauthenticated remote attacker to exploit the vulnerability by sending specially crafted requests to the device's web server, potentially leading to arbitrary code execution or complete device compromise.
The technical nature of this vulnerability aligns with CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking permits writing beyond allocated memory boundaries. The affected devices utilize embedded operating systems that process HTTP requests through web server components that fail to validate the length of input parameters before copying them into local buffers. Attackers can leverage this by crafting HTTP requests containing oversized parameter values that overwrite adjacent memory locations, potentially corrupting program execution flow or injecting malicious code into the device's memory space.
From an operational perspective, this vulnerability creates significant risk for network administrators and end users who rely on these devices for network connectivity and security. The unauthenticated nature of the exploit means that attackers can compromise devices without requiring valid credentials, making it particularly dangerous for home and small office networks where device security is often overlooked. The impact extends beyond individual device compromise to potentially enable attackers to gain persistent access to entire networks, as these devices often serve as gateways for network traffic and may be used to establish command and control channels.
The vulnerability affects a substantial number of NETGEAR consumer and small business devices, with versions predating specific firmware releases indicating that the flaw has existed for several years without proper patching. This widespread exposure across multiple device models demonstrates poor input validation practices in the embedded software development lifecycle, where security considerations were not adequately addressed during the initial design phase. The affected devices include popular models such as the R7000, R6900, EX6000, and various EX and R series routers that are commonly deployed in residential and small office environments.
Network security professionals should implement immediate mitigations including disabling remote management features, implementing network segmentation, and monitoring for suspicious HTTP traffic patterns that may indicate exploitation attempts. The recommended approach involves applying official firmware updates from NETGEAR that address the buffer overflow conditions through proper input validation and bounds checking mechanisms. Additionally, network defenders should consider implementing intrusion detection systems that can identify malformed HTTP requests targeting web interfaces of these devices. Organizations should also conduct thorough inventory assessments to identify all affected devices within their network infrastructure and prioritize patching based on risk assessment and network criticality. The vulnerability demonstrates the importance of proper software security practices including input validation, memory safety mechanisms, and regular security updates as outlined in industry standards such as the OWASP Top Ten and NIST cybersecurity frameworks.