CVE-2021-45629 in CBR750
Summary
by MITRE • 12/26/2021
Certain NETGEAR devices are affected by command injection by an unauthenticated attacker. This affects CBR750 before 4.6.3.6, RBK752 before 3.2.17.12, RBR750 before 3.2.17.12, RBS750 before 3.2.17.12, RBK852 before 3.2.17.12, RBR850 before 3.2.17.12, and RBS850 before 3.2.17.12.
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Analysis
by VulDB Data Team • 12/28/2021
The vulnerability identified as CVE-2021-45629 represents a critical command injection flaw affecting multiple NETGEAR router models within the CBR750, RBK752, RBR750, RBS750, RBK852, RBR850, and RBS850 device families. This security weakness allows unauthenticated attackers to execute arbitrary commands on affected devices, fundamentally compromising the device's integrity and operational security. The vulnerability exists in firmware versions prior to specific patch releases, with affected models requiring updates to versions 4.6.3.6 and 3.2.17.12 respectively for full remediation. The flaw specifically impacts the web-based management interface of these devices, where user-supplied input is not properly sanitized before being processed by the underlying system commands.
From a technical perspective, this command injection vulnerability stems from inadequate input validation within the device's web administration portal. When an attacker submits malicious input through web forms or API endpoints, the system fails to properly escape or filter special characters that could be interpreted as shell commands. This allows attackers to inject operating system commands that execute with the privileges of the web server process, typically running with elevated permissions on the device. The vulnerability aligns with CWE-77 and CWE-89 classifications, representing command injection and SQL injection patterns respectively, though the specific implementation manifests as shell command injection. The attack surface is particularly concerning as it requires no authentication, making exploitation accessible to anyone with network access to the affected devices.
The operational impact of this vulnerability extends beyond simple unauthorized access, creating a pathway for sophisticated attacks that could compromise entire network infrastructures. An attacker could leverage this vulnerability to establish persistent backdoors, redirect network traffic, modify firewall rules, or even exfiltrate sensitive configuration data. The affected devices serve as critical network gateways, making them prime targets for attackers seeking to gain control over larger network segments. This vulnerability enables threat actors to potentially escalate privileges, create unauthorized network connections, or deploy additional malware payloads. The unauthenticated nature of the attack means that network defenders cannot rely on authentication barriers to prevent exploitation, and the vulnerability affects multiple device models within the same product line, amplifying the potential attack surface.
Security mitigations for CVE-2021-45629 primarily involve immediate firmware updates from NETGEAR, which address the input validation flaws in the web interface components. Organizations should prioritize patching all affected devices in their inventory, particularly those deployed in critical network segments or exposed to untrusted networks. Network segmentation strategies should be implemented to limit access to these devices, while monitoring systems should be configured to detect unusual network traffic patterns that might indicate exploitation attempts. The vulnerability's alignment with ATT&CK technique T1059.001 for command and script injection emphasizes the need for comprehensive network monitoring and intrusion detection capabilities. Additionally, network administrators should consider implementing network access control measures, disabling unnecessary services, and conducting regular security assessments to identify other potential vulnerabilities within their network infrastructure. Regular vulnerability scanning and penetration testing should be performed to ensure that all devices remain secure against similar command injection threats.