CVE-2021-45633 in CBR750
Summary
by MITRE • 12/26/2021
Certain NETGEAR devices are affected by command injection by an unauthenticated attacker. This affects CBR750 before 4.6.3.6, RBR750 before 3.2.17.12, RBR850 before 3.2.17.12, RBS750 before 3.2.17.12, RBS850 before 3.2.17.12, RBK752 before 3.2.17.12, and RBK852 before 3.2.17.12.
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Analysis
by VulDB Data Team • 12/28/2021
The vulnerability CVE-2021-45633 represents a critical command injection flaw affecting multiple NETGEAR router models including CBR750, RBR750, RBR850, RBS750, RBS850, RBK752, and RBK852. This security weakness allows unauthenticated attackers to execute arbitrary commands on affected devices, fundamentally compromising the device's integrity and security posture. The vulnerability stems from insufficient input validation within the device's web interface, where user-supplied data is directly incorporated into system commands without proper sanitization or encoding. The affected firmware versions indicate that this flaw existed across multiple generations of NETGEAR's business and residential gateway products, suggesting a systemic issue in the software development lifecycle that affected a broad range of network infrastructure equipment.
The technical exploitation of this vulnerability occurs through the manipulation of input parameters within the device's web administration interface, where attackers can inject malicious commands that get executed with the privileges of the web server process. This command injection allows adversaries to gain unauthorized access to the underlying operating system, potentially enabling them to modify device configuration, install malicious software, or establish persistent backdoors. The lack of authentication requirements means that any remote attacker can exploit this vulnerability without requiring valid credentials, making it particularly dangerous for network infrastructure devices that are typically exposed to external networks. This flaw aligns with CWE-77 and CWE-88 categories, which specifically address command injection vulnerabilities where untrusted data is passed to system commands without proper validation or sanitization.
From an operational impact perspective, this vulnerability creates significant risks for organizations relying on affected NETGEAR devices as network gateways and firewalls. Attackers could potentially disrupt network services, steal sensitive data, or use the compromised devices as entry points for further attacks within the network infrastructure. The vulnerability affects both residential and business-grade routers, meaning that small businesses and large enterprises could be equally impacted. The exposed nature of these devices on public networks makes them prime targets for automated exploitation campaigns, where attackers scan for vulnerable devices and automatically attempt to exploit them. This scenario directly maps to ATT&CK techniques involving remote service exploitation and privilege escalation, where attackers leverage command injection to gain deeper system access and maintain persistent presence within target networks.
Organizations should immediately implement mitigation strategies including firmware updates to the latest available versions that address this vulnerability, network segmentation to isolate affected devices, and monitoring for suspicious network traffic patterns. The affected devices should be taken offline until proper security patches are applied, as the vulnerability allows for complete system compromise without authentication. Network administrators should also consider implementing intrusion detection systems to monitor for exploitation attempts and establish network access controls to limit exposure of these devices to external networks. Additionally, organizations should conduct comprehensive vulnerability assessments to identify any other potentially affected devices within their network infrastructure and ensure proper network monitoring practices are in place to detect unauthorized access attempts. The vulnerability underscores the importance of maintaining up-to-date firmware and implementing proper security controls for network infrastructure devices that are often overlooked in traditional security assessments.