CVE-2018-21189 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.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 06/03/2024
This vulnerability represents a critical stack-based buffer overflow flaw that affects multiple NETGEAR router models, specifically impacting devices in the D6100 R6100 R7800 R9000 WNDR3700v4 WNDR4300 WNDR4300v2 WNDR4500v3 and WNR2000v5 product lines. The vulnerability is particularly concerning because it requires only authenticated access to exploit, meaning an attacker who has already gained user-level credentials on the device can leverage this flaw to execute arbitrary code. The affected firmware versions indicate a widespread issue across various router generations, suggesting this may be a systemic design flaw in the network device's code implementation.
The technical nature of this buffer overflow stems from improper input validation within the device's web interface or management functions, where user-supplied data is copied into insufficiently sized stack buffers without adequate bounds checking. This allows an authenticated user to overflow the buffer and potentially overwrite adjacent memory locations, including return addresses and function pointers. According to CWE-121, this classification describes stack-based buffer overflow conditions where insufficient space is allocated for buffers, leading to memory corruption that can be exploited for privilege escalation or code execution. The vulnerability enables an attacker to gain unauthorized control over the device's operating system, potentially leading to complete network compromise.
The operational impact of this vulnerability extends far beyond simple device exploitation, as compromised routers can serve as persistent footholds for advanced persistent threats. Attackers can use the compromised device as a pivot point to launch further attacks against internal network segments, install backdoors, or redirect traffic through malicious proxies. This aligns with ATT&CK technique T1071.004 for application layer protocol usage and T1059.007 for command and script interpreter. The vulnerability also represents a significant risk to network security posture since routers typically serve as central points of control and monitoring within network infrastructure, making their compromise particularly damaging. Organizations relying on these devices for network segmentation and security controls may experience complete loss of network integrity and visibility.
Mitigation strategies should focus on immediate firmware updates from NETGEAR, as these devices are specifically mentioned in the affected versions. Network administrators should also implement network segmentation to limit the potential impact of any successful exploitation, deploy intrusion detection systems to monitor for anomalous behavior, and conduct thorough network scans to identify any unauthorized access attempts. Additionally, implementing strong authentication controls, regularly updating device firmware, and maintaining detailed network monitoring logs can help detect and prevent exploitation attempts. The vulnerability highlights the importance of secure coding practices and proper input validation, particularly in network device firmware where authenticated users may have elevated privileges and access to system resources that could be exploited for more serious attacks.