CVE-2019-20767 in D6100
Summary
by MITRE
Certain NETGEAR devices are affected by a stack-based buffer overflow by an authenticated user. This affects D6100 before 1.0.0.60, D3600 before 1.0.0.75, D6000 before 1.0.0.75, R9000 before 1.0.4.26, R8900 before 1.0.4.26, R7800 before 1.0.2.52, WNDR4500v3 before 1.0.0.58, WNDR4300v2 before 1.0.0.58, WNDR4300 before 1.0.2.104, WNDR3700v4 before 1.0.2.102, and WNR2000v5 before 1.0.0.66.
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Analysis
by VulDB Data Team • 05/26/2024
The vulnerability identified as CVE-2019-20767 represents a critical stack-based buffer overflow flaw affecting multiple NETGEAR networking devices, with implications for network security and device integrity. This vulnerability exists within the web management interface of affected routers and is exploitable by authenticated users who possess valid credentials to access the device's administrative functions. The flaw stems from inadequate input validation mechanisms within the device's firmware, specifically within the handling of user-supplied data in web forms and configuration parameters. The buffer overflow occurs when the device fails to properly bounds-check data entered through the web interface, allowing maliciously crafted input to overwrite adjacent memory locations on the stack. This type of vulnerability is classified under CWE-121 as a stack-based buffer overflow, which represents one of the most common and dangerous classes of software vulnerabilities in embedded systems and network devices. The affected device models span several generations of NETGEAR routers including various D-series and R-series models, indicating a widespread issue across the vendor's product line.
The operational impact of this vulnerability extends beyond simple denial of service scenarios, as authenticated attackers with access to the device's web interface can potentially execute arbitrary code on the affected systems. The stack-based nature of the overflow means that attackers can manipulate the program's execution flow by overwriting return addresses and function pointers stored on the stack, potentially leading to complete system compromise. This vulnerability particularly affects devices that are commonly deployed in residential and small office environments where network administrators may not regularly update firmware, creating persistent security risks. The exploitation of this flaw requires an authenticated user session, which reduces the attack surface compared to unauthenticated vulnerabilities, but still represents a significant risk since many network administrators leave default credentials unchanged or use weak authentication mechanisms. The affected firmware versions indicate that this vulnerability existed for extended periods without proper mitigation, suggesting that many devices in the field remain vulnerable to exploitation.
Mitigation strategies for CVE-2019-20767 must focus on both immediate remediation and long-term security posture improvements. The most effective immediate solution involves updating all affected devices to the latest firmware versions provided by NETGEAR, which contain patches addressing the buffer overflow conditions. Network administrators should implement strict access controls to limit who can access device management interfaces and ensure that default credentials are changed immediately upon device deployment. The vulnerability's classification under ATT&CK technique T1059.007 for command and scripting interpreter indicates that successful exploitation could lead to lateral movement within networks, making it particularly dangerous in enterprise environments. Organizations should also consider implementing network monitoring solutions to detect anomalous traffic patterns that might indicate exploitation attempts. Security professionals should conduct comprehensive vulnerability assessments of all network devices to identify additional unpatched systems that may be susceptible to similar buffer overflow conditions. The presence of this vulnerability in multiple device generations suggests that similar flaws may exist in other components of the firmware, warranting broader security reviews of the affected product lines. Regular firmware update policies and network segmentation strategies become critical defensive measures to protect against exploitation of this and related vulnerabilities.