CVE-2018-21134 in R6700
Summary
by MITRE
Certain NETGEAR devices are affected by a stack-based buffer overflow by an unauthenticated attacker. This affects R6700 before 1.0.1.48, R7900 before 1.0.2.16, R6900 before 1.0.1.48, R7000P before 1.3.1.44, R6900P before 1.3.1.44, R6250 before 1.0.4.30, R6300v2 before 1.0.4.32, R6400 before 1.0.1.44, R6400v2 before 1.0.2.60, R7000 before 1.0.9.34, R7100LG before 1.0.0.48, R7300 before 1.0.0.68, R8000 before 1.0.4.18, R8000P before 1.4.1.24, R7900P before 1.4.1.24, R8500 before 1.0.2.122, R8300 before 1.0.2.122, WN2500RPv2 before 1.0.1.54, EX3700 before 1.0.0.72, EX3800 before 1.0.0.72, EX6000 before 1.0.0.32, EX6100 before 1.0.2.24, EX6120 before 1.0.0.42, EX6130 before 1.0.0.24, EX6150v1 before 1.0.0.42, EX6200 before 1.0.3.88, EX7000 before 1.0.0.66, D7000v2 before 1.0.0.51, D6220 before 1.0.0.46, D6400 before 1.0.0.82, and D8500 before 1.0.3.42.
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Analysis
by VulDB Data Team • 06/02/2024
This vulnerability represents a critical stack-based buffer overflow condition affecting numerous NETGEAR wireless routers and networking devices, specifically impacting firmware versions prior to the listed patches. The flaw exists within the device's web interface handling mechanism, where unauthenticated attackers can exploit a lack of proper input validation to overwrite adjacent memory locations on the stack. This type of vulnerability falls under CWE-121, which describes stack-based buffer overflow conditions where insufficient bounds checking allows attackers to write beyond allocated memory boundaries. The vulnerability is particularly dangerous because it requires no authentication, making it accessible to anyone on the network or even remotely if the device exposes web interfaces to the internet.
The technical exploitation occurs when an attacker sends specially crafted HTTP requests to the affected device's web server component, specifically targeting parameters that are processed without adequate buffer size validation. The buffer overflow can potentially lead to arbitrary code execution, allowing attackers to gain full control over the affected device. This represents a significant operational risk as these devices typically serve as the primary gateway for network traffic, providing attackers with privileged access to internal network resources. The vulnerability affects a wide range of NETGEAR products including popular models like the R6700, R7900, and R7000 series routers, which are commonly deployed in both residential and small business environments.
The impact of this vulnerability extends beyond simple device compromise, as it can enable attackers to establish persistent access points within networks, potentially leading to data exfiltration, man-in-the-middle attacks, or use as a pivot point for attacking other networked devices. According to ATT&CK framework, this vulnerability maps to T1071.004 for application layer protocol usage and T1059.007 for command and scripting interpreter, as attackers could leverage the compromised device to execute commands or establish remote access. The affected devices include both consumer-grade and enterprise-level networking equipment, making the potential attack surface substantial across various network environments. Organizations should consider this vulnerability as a critical threat that could allow attackers to gain unauthorized access to sensitive network infrastructure.
Mitigation strategies must include immediate firmware updates to the latest versions provided by NETGEAR, as these patches address the buffer overflow conditions through proper input validation and memory boundary checks. Network segmentation should be implemented to limit the attack surface, particularly by restricting access to device management interfaces from external networks. Additional security measures include deploying intrusion detection systems to monitor for suspicious HTTP traffic patterns and implementing network access controls to prevent unauthorized access to device management ports. Security teams should also conduct comprehensive inventory audits to identify all affected devices within their network infrastructure and establish monitoring protocols to detect potential exploitation attempts. The vulnerability demonstrates the importance of maintaining up-to-date firmware across all networked devices and highlights the need for regular security assessments of network infrastructure to identify and remediate similar vulnerabilities before they can be exploited by malicious actors.