CVE-2019-20713 in D8500
Summary
by MITRE
Certain NETGEAR devices are affected by a stack-based buffer overflow by an authenticated user. This affects D8500 before 1.0.3.44, R6250 before 1.0.4.34, R6300v2 before 1.0.4.32, R6400 before 1.0.1.46, R6700 before 1.0.2.6, R6900 before 1.0.2.4, R6900P before 1.3.1.64, R7000 before 1.0.9.42, R7000P before 1.3.1.64, R7100LG before 1.0.0.50, R7300DST before 1.0.0.70, R7900 before 1.0.3.8, R7900P before 1.4.1.30, R8000 before 1.0.4.28, R8000P before 1.4.1.30, R8300 before 1.0.2.128, and R8500 before 1.0.2.128.
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Analysis
by VulDB Data Team • 05/31/2024
This vulnerability represents a critical stack-based buffer overflow condition that affects multiple NETGEAR router models, specifically targeting the administrative web interface. The flaw allows an authenticated attacker to exploit a memory corruption issue that occurs when processing user-supplied input through the device's web management portal. According to the Common Weakness Enumeration catalog, this corresponds to CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to overwrite adjacent memory locations. The vulnerability is particularly concerning because it requires only authentication credentials, making it accessible to anyone with legitimate access to the device's administrative interface.
The technical implementation of this vulnerability occurs within the device's web server component that handles configuration requests submitted through the management interface. When an authenticated user submits malformed input parameters to specific administrative endpoints, the device fails to properly validate input length before copying data to fixed-size stack buffers. This allows an attacker to overflow the buffer and potentially overwrite return addresses, function pointers, or other critical stack data structures. The exploitation typically involves crafting specially formatted HTTP requests that trigger the buffer overflow condition during parameter parsing. The affected devices span multiple generations of NETGEAR routers including the R6250, R6300v2, R6400, and R6900 series, indicating a widespread issue across the vendor's product line.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it creates potential for remote code execution or system compromise when combined with other attack vectors. An authenticated attacker could leverage this vulnerability to gain unauthorized control over the affected devices, potentially leading to complete network compromise. The ATT&CK framework categorizes this type of vulnerability under T1210 - Exploitation of Remote Services, as it represents an exploitation of a service running on the network device. Additionally, the vulnerability could enable attackers to modify device configurations, establish persistent backdoors, or use the compromised device as a pivot point for attacking other network resources. The fact that multiple router models share this vulnerability suggests that the underlying codebase or development practices across these products contain similar buffer handling flaws.
Mitigation strategies should focus on immediate firmware updates from NETGEAR, which address the root cause by implementing proper input validation and bounds checking mechanisms. Network administrators should also implement network segmentation to limit access to administrative interfaces and deploy intrusion detection systems to monitor for suspicious web requests. The vulnerability's requirement for authentication means that strong access controls and credential management practices become critical defensive measures. Organizations should also consider implementing network access controls that restrict administrative interface access to trusted IP addresses and enforce multi-factor authentication where possible. Security monitoring should include detection of anomalous parameter values in web requests that could indicate exploitation attempts. The vulnerability's classification as a stack-based buffer overflow aligns with industry best practices for secure coding that emphasize proper input validation, use of safe string handling functions, and regular security code reviews to prevent such memory corruption issues.