CVE-2021-45591 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-2021-45591 represents a critical command injection flaw affecting multiple NETGEAR router models within the RBK and RBR series. This vulnerability operates under CWE-77 which specifically addresses command injection weaknesses in software applications. The affected devices include RBK752, RBR750, RBS750, RBK852, RBR850, and RBS850 models prior to firmware version 3.2.16.6, indicating a widespread issue across several router families that are commonly deployed in both residential and small office environments.
The technical implementation of this vulnerability stems from insufficient input validation and sanitization within the affected NETGEAR devices' web interface or management protocols. An authenticated user who has access to the device's administrative interface can exploit this flaw by injecting malicious commands that are then executed with elevated privileges. This command injection occurs at the system level where user-supplied input is directly incorporated into system commands without proper sanitization or escaping mechanisms. The vulnerability allows attackers to execute arbitrary code on the affected devices, potentially leading to complete system compromise and unauthorized access to network resources.
From an operational perspective, the impact of this vulnerability extends beyond simple command execution to encompass full system compromise and potential network infiltration. Attackers with valid administrative credentials can leverage this vulnerability to escalate privileges, modify device configurations, redirect network traffic, or establish persistent backdoors. The affected devices operate at the network perimeter, making them prime targets for attackers seeking to gain unauthorized access to internal networks. The vulnerability's exploitation can result in man-in-the-middle attacks, data exfiltration, and disruption of network services. According to ATT&CK framework technique T1059.001, adversaries can use command and scripting interpreters to execute malicious commands, which directly aligns with the nature of this vulnerability. The compromised devices can serve as launching points for further attacks against connected systems, making this vulnerability particularly dangerous in enterprise environments where these routers often serve as network gateways.
Mitigation strategies for CVE-2021-45591 primarily involve immediate firmware updates from NETGEAR to version 3.2.16.6 or later, which address the input validation deficiencies that enable command injection. Network administrators should also implement strict access controls, limiting administrative access to only authorized personnel and employing multi-factor authentication where possible. Regular security audits of network infrastructure should include verification of device firmware versions and monitoring for unauthorized access attempts. The vulnerability demonstrates the importance of input validation and proper sanitization techniques as outlined in OWASP Top 10 2021 category A03: Injection, where command injection represents one of the most critical injection vulnerabilities. Organizations should also consider network segmentation and implementing intrusion detection systems to monitor for suspicious command execution patterns. Given the nature of the vulnerability, continuous monitoring of device logs for unusual command execution patterns becomes essential for early detection of potential exploitation attempts.