CVE-2021-45559 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
This vulnerability represents a critical command injection flaw in NETGEAR networking equipment that allows authenticated users to execute arbitrary commands on affected devices. The vulnerability affects multiple router models including RBK752, RBR750, RBS750, RBK852, RBR850, and RBS850, all prior to firmware version 3.2.16.6. The flaw stems from improper input validation within the device's web interface handling, where user-supplied parameters are directly incorporated into system commands without adequate sanitization or escaping mechanisms. This creates a pathway for privilege escalation attacks where an authenticated attacker can leverage their existing credentials to gain unauthorized control over the device's underlying operating system. The vulnerability is classified under CWE-77 as command injection, which is a well-documented weakness in software development practices where external input is improperly integrated into command execution contexts.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass complete device compromise and potential network infiltration. An authenticated user can exploit this flaw to execute system commands with the privileges of the web server process, which typically runs with administrative rights on these devices. This allows attackers to modify device configurations, install malicious firmware, redirect network traffic, or establish persistent backdoors. The vulnerability is particularly concerning because it requires only authentication credentials, which are often obtained through social engineering, credential stuffing, or other initial compromise techniques. Network attackers can leverage this vulnerability to pivot from a compromised user account into the device's internal network, potentially accessing sensitive data or using the compromised device as a launch point for broader network attacks. The ATT&CK framework categorizes this as privilege escalation and persistence techniques, specifically mapping to T1059 for command and script injection and T1078 for valid accounts.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term security improvements. The primary recommendation is to upgrade all affected devices to firmware version 3.2.16.6 or later, which contains the necessary patches to prevent command injection attacks. Network administrators should also implement network segmentation to limit the potential impact of device compromise and establish monitoring for unusual network activity. Additional defensive measures include disabling unnecessary web interfaces, implementing strong access controls, and regularly auditing device configurations. The vulnerability highlights the importance of secure coding practices and input validation in embedded systems, particularly in network infrastructure devices where a single flaw can compromise entire network segments. Organizations should conduct comprehensive vulnerability assessments to identify other potentially affected devices and ensure proper patch management processes are in place to prevent similar issues in the future.