CVE-2018-21115 in XR500
Summary
by MITRE
NETGEAR XR500 devices before 2.3.2.32 are affected by remote code execution by unauthenticated attackers.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 06/01/2024
The vulnerability identified as CVE-2018-21115 affects NETGEAR XR500 wireless routers and represents a critical remote code execution flaw that allows unauthenticated attackers to gain full system control. This vulnerability exists within the device's web interface handling mechanism, specifically in how the router processes certain input parameters. The flaw enables attackers to execute arbitrary code on the affected devices without requiring any authentication credentials, making it particularly dangerous as it can be exploited from outside the network perimeter. The vulnerability impacts all NETGEAR XR500 models running firmware versions prior to 2.3.2.32, which represents a significant portion of deployed devices in both enterprise and residential networks.
The technical root cause of this vulnerability stems from inadequate input validation and improper sanitization of user-supplied data within the router's web administration interface. When the device processes certain HTTP requests containing malicious payloads, it fails to properly validate or escape input parameters, leading to a classic command injection vulnerability. This weakness allows attackers to inject and execute arbitrary commands on the underlying operating system, which typically runs a Linux-based embedded system. The flaw operates at the application layer and can be triggered through various vectors including GET and POST parameters in web requests, making it accessible through standard web browser exploitation techniques.
The operational impact of CVE-2018-21115 is severe and multifaceted, as it provides attackers with complete control over affected devices. Once exploited, adversaries can access all network services, modify device configurations, install malware, and potentially use the compromised router as a pivot point for attacks against other devices on the local network. The vulnerability also enables attackers to establish persistent backdoors, monitor network traffic, and exfiltrate sensitive data from connected devices. Network administrators face significant challenges in detecting such attacks since the exploitation occurs at the device level and may not generate obvious network signatures. This vulnerability particularly affects organizations that rely on NETGEAR XR500 devices for network infrastructure, as it undermines the fundamental security assumptions of network perimeter defense.
Mitigation strategies for CVE-2018-21115 primarily focus on firmware updates and network segmentation. The most effective immediate solution is to upgrade all affected NETGEAR XR500 devices to firmware version 2.3.2.32 or later, which contains patches addressing the input validation issues. Network administrators should also implement network segmentation to limit the potential impact of successful exploitation, ensuring that compromised devices cannot easily access critical network resources. Additional protective measures include disabling unnecessary services, implementing strict firewall rules, and monitoring network traffic for suspicious activity. According to CWE standards, this vulnerability maps to CWE-77 and CWE-94, representing command injection and improper validation of critical constraints. From an ATT&CK framework perspective, this vulnerability aligns with techniques such as T1059.007 for command and script interpreter and T1071.004 for application layer protocol, highlighting the need for comprehensive network monitoring and endpoint protection measures to detect and prevent exploitation attempts.