CVE-2021-45586 in RBK752
Summary
by MITRE • 12/26/2021
Certain NETGEAR devices are affected by command injection by an authenticated user. This affects RBK752 before 3.2.16.6, RBR750 before 3.2.16.6, RBS750 before 3.2.16.6, RBK852 before 3.2.16.6, RBR850 before 3.2.16.6, and RBS850 before 3.2.16.6.
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Analysis
by VulDB Data Team • 12/28/2021
The vulnerability CVE-2021-45586 represents a critical command injection flaw affecting multiple NETGEAR router models within the RBK and RBR series. This vulnerability resides in the web-based management interface of affected devices, where authenticated users can exploit a lack of proper input validation to inject and execute arbitrary commands on the underlying operating system. The flaw specifically impacts devices running firmware versions prior to 3.2.16.6, making a significant portion of NETGEAR's consumer and small office networking equipment susceptible to exploitation. The affected models include RBK752, RBR750, RBS750, RBK852, RBR850, and RBS850, all of which share the same vulnerable codebase in their web administration interfaces.
The technical implementation of this vulnerability stems from inadequate sanitization of user-supplied input within the device's web management portal. When an authenticated user submits specific parameters through the web interface, the system fails to properly validate or escape these inputs before processing them within the command execution context. This allows an attacker to append malicious commands that get executed with the privileges of the web server process, typically running with administrative privileges on the device. The vulnerability falls under CWE-77 which specifically addresses command injection flaws, where user-controllable data is directly incorporated into system commands without proper validation or sanitization. The flaw essentially creates a path for privilege escalation and remote code execution, as the authenticated user can leverage this weakness to gain full administrative control over the device.
The operational impact of this vulnerability extends beyond simple device compromise, as it creates a persistent threat vector for attackers who can establish long-term access to network infrastructure. Once exploited, the attacker gains complete control over the affected router, enabling them to modify network configurations, redirect traffic, monitor communications, and potentially use the device as a pivot point for attacking other systems within the local network. The vulnerability is particularly concerning because it requires only authentication, meaning that anyone with legitimate access credentials can exploit it, including family members, employees, or any authorized user who might have access to the device's web interface. This makes it a significant risk for home networks and small office environments where device access might not be strictly controlled. According to ATT&CK framework, this vulnerability maps to T1059.001 (Command and Scripting Interpreter: PowerShell) and T1021.001 (Remote Services: Remote Desktop Protocol) as attackers can leverage the command injection to execute arbitrary code and potentially establish persistent access to the network.
Mitigation strategies for this vulnerability center around immediate firmware updates to version 3.2.16.6 or later, which contain the necessary patches to address the input validation issues. Network administrators should also implement strict access controls, ensuring that only authorized personnel have administrative access to network devices and that strong authentication mechanisms are in place. Additional defensive measures include network segmentation to limit the potential impact of device compromise, monitoring for unusual network traffic patterns that might indicate exploitation attempts, and implementing network access controls to prevent unauthorized access to device management interfaces. Organizations should also consider disabling web management interfaces when not actively needed and instead rely on secure remote access protocols that provide better authentication and authorization controls. The vulnerability highlights the importance of regular firmware updates and proper input validation in embedded systems, as these devices often serve as critical network infrastructure components where security flaws can have cascading effects throughout the entire network ecosystem.