CVE-2021-45599 in CBR40
Summary
by MITRE • 12/26/2021
Certain NETGEAR devices are affected by command injection by an authenticated user. This affects CBR40 before 2.5.0.24, CBR750 before 4.6.3.6, 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
This vulnerability represents a critical command injection flaw in NETGEAR networking equipment that allows authenticated users to execute arbitrary commands on affected devices. The vulnerability affects multiple device models including CBR40, CBR750, RBK852, RBR850, and RBS850 routers and access points, with specific versions prior to the listed firmware updates being impacted. The flaw stems from insufficient input validation and sanitization within the device's web management interface, where user-supplied parameters are directly incorporated into system commands without proper escaping or filtering mechanisms.
The technical implementation of this vulnerability involves the improper handling of user input within the device's command execution pipeline. When authenticated users access the web interface and submit malicious input through specific parameters, the system fails to properly sanitize these inputs before passing them to underlying system commands. This creates an environment where attackers can inject shell commands that execute with the privileges of the web server process, typically running with elevated permissions on the device. The vulnerability is categorized under CWE-77 as "Improper Neutralization of Special Elements used in a Command ('Command Injection')", which is a well-documented weakness in software security that has been consistently exploited in various network device implementations.
From an operational perspective, this vulnerability poses significant risks to network security infrastructure. An authenticated attacker with access to the device's web management interface can leverage this flaw to gain complete control over the affected networking equipment. The impact extends beyond simple command execution to include potential data exfiltration, network reconnaissance, and the ability to establish persistent access points within the network. Attackers could potentially use this vulnerability to redirect network traffic, disable security features, or even use the compromised devices as launching points for attacks against other network segments. The ATT&CK framework categorizes this as a privilege escalation technique under T1068, where attackers exploit weaknesses in authentication and authorization to gain elevated system privileges.
The exploitation of this vulnerability requires an authenticated session, which limits its scope compared to unauthenticated attacks, but still represents a serious security concern. Network administrators must consider that compromised user credentials could be leveraged to achieve this attack vector, making credential protection and access control critical defensive measures. Organizations should implement network segmentation to limit the potential impact of such compromises and ensure that administrative access is restricted to authorized personnel only. The vulnerability highlights the importance of maintaining up-to-date firmware and conducting regular security assessments of network infrastructure components. Immediate remediation efforts should include applying the vendor-provided firmware updates, implementing network monitoring to detect suspicious command execution patterns, and reviewing access controls to ensure that only necessary personnel have administrative privileges to these devices. Additionally, organizations should consider implementing network access controls and firewalls to limit direct access to administrative interfaces, reducing the attack surface for such vulnerabilities.