CVE-2018-21199 in D7800
Summary
by MITRE
Certain NETGEAR devices are affected by a stack-based buffer overflow by an authenticated user. This affects D7800 before 1.0.1.30, R6100 before 1.0.1.22, R7500 before 1.0.0.122, R7500v2 before 1.0.3.24, R7800 before 1.0.2.40, R9000 before 1.0.2.52, and WNDR4300 before 1.0.2.98.
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Analysis
by VulDB Data Team • 06/03/2024
This vulnerability represents a critical stack-based buffer overflow flaw in NETGEAR wireless routers and networking equipment that affects multiple device models including the D7800, R6100, R7500, R7500v2, R7800, R9000, and WNDR4300. The vulnerability occurs when an authenticated user sends specially crafted input to the device's web interface, exploiting a flaw in the processing of user-supplied data within the device's firmware. The stack-based buffer overflow allows an attacker with legitimate credentials to potentially execute arbitrary code on the affected devices, which could lead to complete system compromise and unauthorized access to the network infrastructure.
The technical implementation of this vulnerability stems from improper input validation within the device's web management interface where user-provided parameters are not adequately checked for length or content before being copied into fixed-size buffers on the stack. This flaw aligns with CWE-121 Stack-based Buffer Overflow, which occurs when data is written beyond the bounds of a stack buffer, potentially overwriting adjacent memory locations including return addresses and function pointers. The vulnerability requires authentication because the attack vector involves sending malicious input through the device's web interface, which is only accessible to users with valid login credentials. This authentication requirement reduces the attack surface but does not eliminate the risk, as the vulnerability can be exploited by insiders or compromised accounts.
The operational impact of this vulnerability extends beyond simple unauthorized access to include potential complete system compromise and persistent backdoor installation. An authenticated attacker could leverage this vulnerability to gain root-level access to the device, allowing them to modify network configurations, install malicious firmware, or use the device as a pivot point for attacks against other networked systems. The vulnerability affects devices running firmware versions prior to the specified patches, meaning that organizations with multiple affected devices would need to implement comprehensive patch management procedures to address the risk. According to ATT&CK framework, this vulnerability maps to T1059 Command and Scripting Interpreter and T1068 Exploitation for Privilege Escalation, as it enables an attacker to execute arbitrary code and escalate privileges within the network infrastructure.
Organizations should immediately implement mitigation strategies including mandatory firmware updates for all affected device models, network segmentation to limit access to administrative interfaces, and monitoring for suspicious login patterns or unusual network activity. The patching process should be prioritized as these devices represent critical network infrastructure components that could provide attackers with persistent access to entire network segments. Network administrators should also consider implementing network access control lists to restrict access to device management interfaces to only authorized personnel and locations, reducing the attack surface for authenticated exploits. The vulnerability demonstrates the importance of secure coding practices and proper input validation in embedded network devices, as similar flaws in network infrastructure can have cascading effects throughout enterprise networks and potentially lead to significant data breaches or service disruptions.