CVE-2018-21177 in D6100
Summary
by MITRE
Certain NETGEAR devices are affected by a stack-based buffer overflow by an authenticated user. This affects D6100 before 1.0.0.57, R6100 before 1.0.1.20, R7800 before 1.0.2.40, R9000 before 1.0.2.52, WNDR3700v4 before 1.0.2.92, WNDR4300 before 1.0.2.94, WNDR4300v2 before 1.0.0.50, WNDR4500v3 before 1.0.0.50, and WNR2000v5 before 1.0.0.62.
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Analysis
by VulDB Data Team • 06/03/2024
This vulnerability represents a critical stack-based buffer overflow flaw in NETGEAR networking equipment that enables authenticated users to execute arbitrary code remotely. The vulnerability stems from improper input validation within the device's web interface handling mechanisms, where user-supplied data is copied to insufficiently sized memory buffers without adequate bounds checking. This particular flaw affects multiple router models including D6100, R6100, R7800, R9000, and various WNDR and WNR series devices, with specific firmware version thresholds indicating the scope of affected installations. The vulnerability resides in the authentication and session management components of the device's web administration interface, where crafted input parameters can overwrite adjacent stack memory regions.
The technical implementation of this buffer overflow occurs when authenticated users submit specially crafted data to web forms or API endpoints within the device's management interface. The flaw manifests as a classic stack-based buffer overflow where the vulnerable code fails to validate the length of user input before copying it to a fixed-size buffer on the stack. This allows an attacker with valid credentials to potentially overwrite return addresses, function pointers, or other critical stack data structures, ultimately enabling code execution with the privileges of the web server process. The vulnerability aligns with CWE-121 stack-based buffer overflow classification and represents a significant escalation path from authenticated access to remote code execution.
The operational impact of this vulnerability extends beyond simple privilege escalation, as it provides attackers with persistent access to network infrastructure that can be leveraged for various malicious activities. Once exploited, the attacker gains the ability to modify router configurations, redirect traffic, establish backdoors, or use the device as a pivot point for further attacks within the local network. The affected devices typically operate in environments with high network traffic and sensitive data flows, making the potential attack surface particularly valuable. This vulnerability directly maps to attack techniques described in the MITRE ATT&CK framework under T1059 command and scripting interpreter and T1068 local privilege escalation, with potential for lateral movement through the compromised network infrastructure.
Mitigation strategies for this vulnerability require immediate firmware updates from NETGEAR to address the buffer overflow conditions in affected device models. Organizations should implement network segmentation to limit access to administrative interfaces and enforce strong authentication controls including multi-factor authentication where possible. Network monitoring should be enhanced to detect unusual traffic patterns or configuration changes that might indicate exploitation attempts. Device administrators should also consider implementing network access control lists to restrict administrative access to trusted IP ranges and establish regular vulnerability scanning schedules. The vulnerability highlights the importance of secure coding practices and proper input validation as outlined in OWASP Top 10 security principles, particularly focusing on preventing injection flaws that could lead to buffer overflow conditions. Regular firmware update policies and network device inventory management become critical defensive measures against similar vulnerabilities in embedded networking equipment.