CVE-2021-45563 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-2021-45563 represents a critical command injection flaw affecting multiple NETGEAR router models including RBK752, RBR750, RBS750, RBK852, RBR850, and RBS850. This issue arises from insufficient input validation within the web management interface of these devices, allowing authenticated users to execute arbitrary commands on the underlying operating system. The vulnerability specifically impacts firmware versions prior to 3.2.16.6, indicating that manufacturers released patches to address this security weakness. From a cybersecurity perspective, this represents a privilege escalation vulnerability where legitimate users with access to the device management interface can leverage this flaw to gain unauthorized control over the network infrastructure.
The technical implementation of this command injection vulnerability stems from improper sanitization of user inputs passed to system commands within the device's web interface. When an authenticated user submits malicious input through web forms or API endpoints, the application fails to properly validate or escape the input before incorporating it into system calls. This allows attackers to inject shell commands that execute with the privileges of the web server process, typically running with elevated system permissions. The vulnerability aligns with CWE-77 and CWE-89, which classify command injection and SQL injection respectively, though the specific implementation in this case involves shell command execution rather than database queries. The attack vector requires an authenticated session, meaning that an attacker must first obtain valid credentials to the device management interface before exploiting this vulnerability.
The operational impact of CVE-2021-45563 extends beyond simple privilege escalation to encompass full network infrastructure compromise. Once exploited, an attacker could gain complete control over the affected router, enabling them to redirect traffic, implement man-in-the-middle attacks, disable security features, or establish persistent backdoors. This vulnerability particularly affects enterprise and home network environments where these routers serve as critical gateways, potentially allowing attackers to compromise the entire network perimeter. The affected devices operate in environments where they handle sensitive network traffic, making the potential for data exfiltration or network disruption significant. Organizations using these vulnerable devices face elevated risk of lateral movement within their networks, as routers often serve as central points for network access control and traffic routing.
Mitigation strategies for this vulnerability should prioritize immediate firmware updates to version 3.2.16.6 or later, as provided by NETGEAR. Network administrators should also implement strict access controls, including strong authentication mechanisms, multi-factor authentication, and regular credential rotation. Additionally, network segmentation and monitoring should be enhanced to detect unauthorized access attempts or unusual traffic patterns that might indicate exploitation attempts. From an ATT&CK framework perspective, this vulnerability maps to techniques involving privilege escalation and command execution, specifically T1059.001 for command and script interpreters and T1547.001 for registry run keys. Security teams should also consider implementing network intrusion detection systems to monitor for known exploit signatures and anomalous command execution patterns that could indicate exploitation attempts. Regular vulnerability assessments and penetration testing should be conducted to identify similar weaknesses in other network infrastructure components.