CVE-2021-45533 in EX6120
Summary
by MITRE • 12/26/2021
Certain NETGEAR devices are affected by command injection by an authenticated user. This affects EX6120 before 1.0.0.66, EX6130 before 1.0.0.46, EX7000 before 1.0.1.106, EX7500 before 1.0.1.76, EX3700 before 1.0.0.94, EX3800 before 1.0.0.94, RBR850 before 4.6.3.9, RBS850 before 4.6.3.9, and RBK852 before 4.6.3.9.
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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 issue stems from inadequate input validation within the web management interface of various EX and RBR series routers and access points. The vulnerability affects multiple device models including EX6120, EX6130, EX7000, EX7500, EX3700, EX3800, RBR850, RBS850, and RBK850 series, with specific firmware version thresholds indicating the scope of impacted installations. The flaw enables a malicious actor with valid credentials to inject and execute system commands, potentially compromising the entire network infrastructure. This represents a significant security weakness that violates fundamental principles of secure programming and input sanitization. The vulnerability aligns with CWE-77 which describes command injection flaws where untrusted data is incorporated into system commands without proper validation or escaping. From an operational perspective, this vulnerability creates a persistent threat vector that could allow attackers to escalate privileges, gain unauthorized access to network resources, or even take complete control of the affected devices. The impact extends beyond individual device compromise to potentially undermine the security posture of entire networks that rely on these devices for connectivity and access control. Attackers could leverage this vulnerability to establish persistent backdoors, redirect network traffic, or launch further attacks against internal network resources. The authentication requirement does not mitigate the risk significantly since compromised credentials often occur through social engineering, credential reuse, or other attack vectors that are common in enterprise environments.
The technical implementation of this vulnerability demonstrates a failure in proper input sanitization and command construction within the device management interface. When legitimate users submit commands through the web interface, the system fails to properly validate or escape user-supplied input before incorporating it into system commands. This allows attackers to inject malicious command sequences that are then executed with the privileges of the web interface user. The affected firmware versions indicate that this was a widespread issue across multiple product lines, suggesting either a shared codebase or similar implementation flaws in the management interface components. The vulnerability's presence in both enterprise and consumer-grade devices underscores the critical nature of the flaw, as it affects products deployed in various environments including home networks, small offices, and large enterprise infrastructures. From a threat modeling perspective, this vulnerability maps directly to ATT&CK technique T1059.001 which covers command and scripting interpreter execution, and T1078 which covers valid accounts for maintaining access. The authentication requirement reduces the attack surface but does not eliminate the risk, particularly in environments where credential compromise is likely or where users may have elevated privileges. The vulnerability's exploitation typically requires a user to be logged into the device's management interface, but once exploited, the attacker can leverage the compromised device as a pivot point for further network reconnaissance and lateral movement.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security posture improvements. The primary recommendation involves updating all affected devices to the latest firmware versions provided by NETGEAR, which contain patches addressing the command injection vulnerability. Organizations should conduct comprehensive inventory assessments to identify all affected devices within their network infrastructure and prioritize remediation based on risk exposure. Network segmentation and access control measures should be implemented to limit the potential impact of device compromise, particularly in enterprise environments where multiple devices may be interconnected. Regular security assessments and vulnerability scanning should be conducted to identify similar issues in other network equipment. The vulnerability highlights the importance of secure coding practices and input validation, particularly for web-based management interfaces. Organizations should implement network monitoring solutions to detect unusual command execution patterns that might indicate exploitation attempts. Additionally, implementing multi-factor authentication and privilege separation for device management access can significantly reduce the risk of unauthorized access. The remediation process should include verification that the firmware updates have been successfully applied and that no unauthorized modifications have been made to device configurations. Regular patch management processes should be established to ensure timely deployment of security updates for all network infrastructure components. The vulnerability also underscores the need for comprehensive security awareness training for network administrators to prevent credential compromise through social engineering or other attack vectors that could enable exploitation of similar vulnerabilities.