CVE-2021-45627 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, RBK852 before 3.2.17.12, RBR850 before 3.2.17.12, and RBS850 before 3.2.17.12.
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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 unauthenticated attackers to execute arbitrary commands on affected devices. The vulnerability specifically impacts several router models including the CBR750, RBK852, RBR850, and RBS850, all of which are susceptible when running firmware versions prior to the specified patches. The command injection vulnerability arises from improper input validation within the device's web interface or management protocols, enabling remote attackers to inject malicious commands that are then executed with the privileges of the affected service. This weakness falls under the common weakness enumeration CWE-77 which categorizes improper neutralization of special elements used in commands, making it particularly dangerous as it can lead to complete device compromise.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it provides attackers with the ability to execute arbitrary code on network infrastructure devices. An unauthenticated attacker can leverage this flaw to gain full control over the affected routers, potentially leading to man-in-the-middle attacks, network traffic interception, or redirection of network traffic. The vulnerability's severity is compounded by the fact that it affects multiple device models within the NETGEAR product line, suggesting a systemic issue in the firmware implementation that could affect a significant portion of deployed network infrastructure. Attackers could use this vulnerability to establish persistent backdoors, modify network configurations, or use the compromised devices as launching points for further attacks against the internal network.
From a cybersecurity perspective, this vulnerability aligns with tactics and techniques documented in the ATT&CK framework under the execution and privilege escalation domains. The ability to execute commands without authentication directly maps to techniques such as command injection and remote code execution, while the privilege escalation aspect can be leveraged to gain administrative control over network infrastructure. The vulnerability's presence in network routing equipment makes it particularly concerning for enterprise and industrial environments where these devices form the backbone of network connectivity and security. Organizations should consider this vulnerability as a potential indicator of broader security weaknesses in their network infrastructure, as it demonstrates the potential for attackers to compromise fundamental network control points. The lack of authentication requirements for exploitation means that this vulnerability can be leveraged by anyone with network access, making it particularly dangerous in environments where network segmentation is insufficient.
The recommended mitigation strategy involves immediate firmware updates to the patched versions mentioned in the CVE advisory, specifically versions 4.6.3.6 for CBR750 and 3.2.17.12 for the other affected models. Network administrators should also implement network segmentation and access controls to limit exposure of these devices to untrusted networks. Additional protective measures include monitoring network traffic for suspicious command execution patterns, implementing intrusion detection systems, and conducting thorough vulnerability assessments of all network infrastructure devices. The vulnerability highlights the importance of maintaining up-to-date firmware and the critical need for robust input validation in network device software to prevent similar command injection scenarios. Organizations should also consider implementing network access control lists to restrict access to management interfaces and establish baseline configurations that minimize attack surface.