CVE-2021-45562 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-2021-45562 represents a critical command injection flaw affecting multiple NETGEAR router models within the RBK and RBR series. This security weakness allows authenticated attackers to execute arbitrary commands on affected devices, potentially compromising the entire network infrastructure. The vulnerability specifically impacts devices running firmware versions prior to 3.2.16.6, including RBK752, RBR750, RBS750, RBK852, RBR850, and RBS850 models. The affected hardware represents a significant portion of NETGEAR's consumer and small business networking equipment, making this vulnerability particularly concerning from a widespread impact perspective.
The technical flaw stems from insufficient input validation and sanitization within the device's web interface authentication system. When an authenticated user submits malicious input through specific parameters, the system fails to properly escape or filter the input before executing it as a command. This vulnerability falls under CWE-77 which specifically addresses command injection flaws in software applications. The weakness creates a path for attackers to bypass normal authentication mechanisms and execute arbitrary system commands with the privileges of the authenticated user. This type of vulnerability is particularly dangerous because it requires only a valid user account to exploit, which may be obtained through various means including credential theft, social engineering, or default credential exploitation.
The operational impact of this vulnerability extends far beyond simple unauthorized access. An attacker with authenticated access can potentially gain complete control over the affected network devices, enabling them to modify network configurations, redirect traffic, install malicious software, or use the devices as launch points for further attacks against connected systems. The compromised devices may serve as persistent backdoors, allowing attackers to maintain long-term access to the network. From an attack chain perspective, this vulnerability aligns with ATT&CK technique T1059.001 for command and script interpreter, and T1078 for valid accounts, as it leverages legitimate user credentials to execute malicious commands. The threat landscape is further complicated by the fact that these devices often serve as network gateways, making them prime targets for lateral movement and privilege escalation attacks.
Mitigation strategies for CVE-2021-45562 primarily focus on firmware updates and network segmentation. NETGEAR has released firmware versions 3.2.16.6 and later that address this vulnerability through proper input validation and sanitization mechanisms. Organizations should immediately update all affected devices to the latest firmware versions available from NETGEAR's official website. Network administrators should also implement strict network segmentation to limit the potential impact of a compromised device. Additional security measures include monitoring network traffic for unusual command execution patterns, implementing strong authentication controls, and regularly auditing device configurations. The vulnerability demonstrates the importance of proper input validation in web applications and highlights the need for continuous security testing of network infrastructure devices. Security teams should also consider implementing network intrusion detection systems to monitor for exploitation attempts and maintain comprehensive incident response procedures to address potential breaches.