CVE-2018-21202 in D7800
Summary
by MITRE
Certain NETGEAR devices are affected by a stack-based buffer overflow by an unauthenticated attacker. This affects D7800 before 1.0.1.30, R6100 before 1.0.1.20, R7500 before 1.0.0.118, R7500v2 before 1.0.3.24, R7800 before 1.0.2.40, R9000 before 1.0.2.52, WNDR3700v4 before 1.0.2.96, WNDR4300 before 1.0.2.98, WNDR4300v2 before 1.0.0.54, and WNDR4500v3 before 1.0.0.54.
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Analysis
by VulDB Data Team • 06/03/2024
This vulnerability represents a critical stack-based buffer overflow flaw that affects multiple NETGEAR wireless routers and networking devices, creating a significant security risk for affected networks. The vulnerability stems from improper input validation within the device's web interface handling mechanisms, where an attacker can exploit a buffer overflow condition by sending specially crafted data to the device's HTTP server. This flaw allows an unauthenticated remote attacker to execute arbitrary code on the affected devices, potentially leading to complete system compromise and unauthorized network access. The vulnerability exists in firmware versions prior to the specified updates for each affected model, indicating that the issue was present in the software implementations for years before detection and remediation.
The technical exploitation of this vulnerability occurs through network-based attacks targeting the device's web administration interface, where the buffer overflow can be triggered by sending malformed HTTP requests or parameters to the affected routers. This type of vulnerability maps directly to CWE-121 Stack-based Buffer Overflow, which is classified as a critical weakness in software security that occurs when data is written beyond the bounds of a fixed-length stack buffer. The attack vector is particularly dangerous because it requires no authentication, making it accessible to anyone on the network or even remotely if the device is exposed to the internet. According to the ATT&CK framework, this vulnerability aligns with T1210 Exploitation of Remote Services, as it leverages unauthenticated access to network services to achieve remote code execution.
The operational impact of this vulnerability extends far beyond simple device compromise, as affected routers could become part of botnets, serve as pivoting points for internal network attacks, or provide persistent backdoors for malicious actors. Network administrators face significant risk of unauthorized access to their entire network infrastructure, as these devices typically serve as the primary gateway for network traffic and often contain sensitive configuration data. The widespread nature of affected models means that organizations with multiple NETGEAR devices could experience cascading security failures, where a single compromised device provides attackers with access to the broader network ecosystem. This vulnerability also represents a potential denial of service condition, as successful exploitation could cause devices to crash or reboot, disrupting network connectivity and service availability.
Mitigation strategies for this vulnerability require immediate firmware updates from NETGEAR, as the company has released patches for all affected models to address the buffer overflow condition. Network administrators should prioritize updating all affected devices to the latest firmware versions, which contain proper input validation and buffer management controls to prevent the exploitation. Additional defensive measures include implementing network segmentation to isolate affected devices, disabling unnecessary services and remote administration features, and monitoring network traffic for suspicious activity that might indicate exploitation attempts. The vulnerability also highlights the importance of regular security assessments and firmware monitoring, as many organizations may not be aware of the presence of these vulnerable devices on their networks. Organizations should also consider implementing intrusion detection systems to monitor for exploitation attempts and establish incident response procedures to quickly address any successful compromise of affected devices.