CVE-2021-45566 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-2021-45566 represents a critical command injection flaw affecting multiple NETGEAR router models including RBK752, RBR750, RBS750, RBK852, RBR850, and RBS850. This vulnerability resides in the web-based management interface of these devices and allows authenticated users to execute arbitrary commands on the underlying operating system. The flaw stems from insufficient input validation and sanitization within the device's web server component, specifically in how it processes user-supplied parameters. Attackers who have gained valid login credentials can exploit this vulnerability to execute malicious commands with the privileges of the web server process, potentially leading to complete device compromise.
The technical implementation of this command injection vulnerability occurs when the device's web interface fails to properly sanitize user input before incorporating it into system commands. This typically manifests in scenarios where parameters passed to the web server are directly concatenated into shell commands without adequate filtering or escaping mechanisms. The affected versions prior to 3.2.16.6 lack proper input validation controls, allowing attackers to inject malicious command sequences that get executed by the underlying operating system. This vulnerability falls under CWE-77 which specifically addresses command injection flaws in software applications. The issue is particularly concerning because it requires only authentication credentials rather than elevated privileges, making it accessible to anyone who can establish a valid session with the device.
The operational impact of this vulnerability extends beyond simple device compromise to include potential network infiltration and lateral movement within corporate environments. Once an attacker gains command execution capability, they can modify device configurations, redirect traffic, establish backdoors, or use the compromised device as a pivot point for attacking other network resources. This aligns with ATT&CK technique T1059.001 for command and scripting interpreter and T1021.001 for remote services. Organizations using these affected NETGEAR devices face significant risk as the vulnerability could enable attackers to maintain persistent access to their network infrastructure, potentially remaining undetected for extended periods. The compromised devices may also serve as staging points for more sophisticated attacks including data exfiltration or deployment of additional malware.
Mitigation strategies for CVE-2021-45566 primarily focus on updating affected devices to the patched versions released by NETGEAR. Users should immediately upgrade their devices to firmware version 3.2.16.6 or later, which includes proper input validation and sanitization measures. Network administrators should also implement additional security controls including disabling unnecessary web management interfaces, restricting access to device management portals through firewall rules, and employing network segmentation to limit the potential impact of successful exploitation. Regular security audits and monitoring of device logs for suspicious activity should be conducted to detect potential exploitation attempts. The vulnerability demonstrates the importance of secure coding practices and input validation in embedded network devices, as highlighted in industry standards such as the OWASP Top Ten and NIST cybersecurity frameworks. Organizations should also consider implementing network access control measures and regular vulnerability assessments to identify and remediate similar issues across their entire network infrastructure.