CVE-2021-45578 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 identified as CVE-2021-45578 represents a critical command injection flaw affecting multiple NETGEAR router models within the RBK and RBR series. This security weakness allows authenticated attackers to execute arbitrary commands on affected devices, potentially leading to complete system compromise and unauthorized network access. The vulnerability specifically impacts devices running firmware versions prior to 3.2.16.6, including the RBK752, RBR750, RBS750, RBK852, RBR850, and RBS850 models. The flaw stems from inadequate input validation and sanitization within the device's web interface, which processes user-supplied parameters without proper security controls.
The technical implementation of this vulnerability resides in the web management interface of these routers, where user input is directly incorporated into system commands without appropriate filtering or escaping mechanisms. When an authenticated user submits malicious input through specific web forms or parameters, the system processes these inputs without proper validation, allowing attackers to inject shell commands that execute with the privileges of the web server process. This type of vulnerability maps directly to CWE-77, which describes improper neutralization of special elements used in a command inside a web page, commonly known as command injection. The attack vector typically involves manipulating form fields, URL parameters, or API endpoints that handle user input and subsequently pass it to system commands.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it provides attackers with complete control over the affected router's functionality. Once exploited, an attacker can modify network configurations, redirect traffic, implement man-in-the-middle attacks, or establish persistent backdoors within the network infrastructure. The authenticated nature of this vulnerability means that attackers must first obtain valid credentials, but this requirement does not significantly mitigate the risk given that many network administrators use default passwords or weak authentication mechanisms. The affected devices serve as critical network gateways, making them prime targets for attackers seeking to establish persistent access to corporate or residential networks. This vulnerability aligns with ATT&CK technique T1059.001, which covers command and scripting interpreter, specifically focusing on the execution of commands through legitimate system interfaces.
Mitigation strategies for CVE-2021-45578 primarily involve firmware updates from NETGEAR, which address the command injection vulnerability by implementing proper input validation and sanitization measures. Organizations should immediately upgrade all affected devices to firmware version 3.2.16.6 or later, as this update resolves the underlying security flaw. Additionally, network administrators should implement network segmentation to limit the potential impact of compromised devices, enforce strong authentication practices with unique passwords, and monitor network traffic for suspicious activities. The remediation process should include comprehensive vulnerability assessments of all network devices to identify similar weaknesses, particularly those following the same software architecture patterns. Security teams should also consider implementing network monitoring solutions that can detect anomalous command execution patterns and establish incident response procedures specifically addressing router compromise scenarios. The vulnerability demonstrates the critical importance of secure coding practices and input validation in network infrastructure devices, as even authenticated access can lead to complete system compromise when proper security controls are absent.