CVE-2021-45571 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-2021-45571 represents a critical command injection flaw affecting multiple NETGEAR router models within the RBK and RBR series. This security weakness allows authenticated attackers with valid credentials to execute arbitrary commands on affected devices, potentially leading to complete system compromise and unauthorized network access. The vulnerability specifically impacts firmware versions prior to 3.2.16.6 across several router models including RBK752, RBR750, RBS750, RBK852, RBR850, and RBS850. The flaw stems from inadequate input validation and sanitization within the device's web interface handling mechanisms, creating an avenue for malicious command execution through specially crafted user inputs.
This command injection vulnerability operates at the application layer and falls under the Common Weakness Enumeration category CWE-77, which specifically addresses command injection flaws in software applications. The vulnerability enables an authenticated attacker to bypass normal access controls and execute system commands with the privileges of the web server process, typically running with administrative privileges on the device. The impact extends beyond simple command execution as it can lead to complete system compromise, data exfiltration, and potential lateral movement within network environments where these devices operate. Attackers could leverage this vulnerability to install backdoors, modify network configurations, or redirect traffic through the compromised devices, making them effective entry points for broader network attacks.
The operational implications of this vulnerability are severe for organizations relying on NETGEAR routers, as the affected devices serve as critical network infrastructure components. Once compromised, these routers can become persistent attack platforms that provide attackers with continuous access to internal network resources. The authentication requirement does not significantly mitigate the risk since these devices are often deployed in environments where physical access or legitimate administrative credentials may be obtained through social engineering or credential theft. Network administrators should consider that these devices may be targeted by advanced persistent threat actors who seek long-term access to network infrastructure. The vulnerability also aligns with ATT&CK framework technique T1059.001, which covers command and script injection through web applications, and T1021.001, covering remote services through network infrastructure devices.
Mitigation strategies for CVE-2021-45571 primarily involve immediate firmware updates to versions 3.2.16.6 or later, which contain patches addressing the command injection vulnerability. Organizations should conduct comprehensive inventory assessments to identify all affected devices and prioritize their remediation based on network criticality and exposure levels. Network segmentation and access control measures should be implemented to limit the potential impact of compromised devices, while monitoring systems should be enhanced to detect anomalous command execution patterns. Additional protective measures include disabling unnecessary web management interfaces, implementing strong authentication mechanisms, and regularly reviewing access logs for suspicious activities. Security teams should also consider deploying network intrusion detection systems to monitor for exploitation attempts and maintain updated threat intelligence feeds to identify potential related attacks targeting similar vulnerabilities in network infrastructure components.