CVE-2021-45546 in R7850
Summary
by MITRE • 12/26/2021
Certain NETGEAR devices are affected by command injection by an authenticated user. This affects R7850 before 1.0.5.74, R7900P before 1.4.2.84, R7960P before 1.4.2.84, R8000 before 1.0.4.74, R8000P before 1.4.2.84, RAX200 before 1.0.4.120, RAX75 before 1.0.4.120, RAX80 before 1.0.4.120, RBK752 before 3.2.17.12, RBK852 before 3.2.17.12, RBR750 before 3.2.17.12, RBR850 before 3.2.17.12, RBS750 before 3.2.17.12, and RBS850 before 3.2.17.12.
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Analysis
by VulDB Data Team • 12/28/2021
The vulnerability CVE-2021-45546 represents a critical command injection flaw affecting multiple NETGEAR networking devices, specifically targeting routers and wireless access points across various product lines. This authentication-based vulnerability allows an attacker who has already gained access to a device to execute arbitrary commands with elevated privileges, potentially compromising the entire network infrastructure. The affected devices span several models including the R7850, R7900P, R8000, and various RAX and RBK series routers, with specific firmware versions indicating the scope of impacted hardware. The vulnerability exists in the web management interface of these devices, where user input is not properly sanitized before being processed as system commands, creating a direct pathway for malicious command execution.
This command injection vulnerability falls under CWE-77, which specifically addresses command injection flaws in software applications. The flaw occurs when user-supplied data is directly incorporated into system command execution without proper validation or sanitization, allowing attackers to inject malicious commands that are then executed by the underlying operating system. The vulnerability is particularly concerning because it requires only authenticated access, meaning that an attacker who has already compromised user credentials or gained physical access to the device can escalate privileges and execute arbitrary code. The affected NETGEAR devices typically run embedded Linux systems with web servers that handle administrative requests, making them susceptible to this type of injection attack. Attackers can leverage this vulnerability to gain complete control over the device, potentially using it as a pivot point for further network infiltration or to establish persistent backdoors.
The operational impact of CVE-2021-45546 extends beyond individual device compromise to potentially affect entire network infrastructures. Once an attacker gains command execution capabilities, they can modify device configurations, redirect traffic, install malicious firmware, or use the compromised device as a launchpad for attacks against other network segments. The vulnerability enables potential data exfiltration from the device, modification of network settings, and establishment of persistent access points that could remain undetected for extended periods. Network administrators face significant challenges in detecting such attacks since legitimate administrative commands may appear in system logs, making malicious activity blend seamlessly with normal operations. The affected device models represent a substantial portion of NETGEAR's consumer and small business product lineup, meaning that organizations of various sizes could be impacted, from home users to small office networks and potentially larger enterprise deployments that may have deployed these devices.
Mitigation strategies for this vulnerability should prioritize immediate firmware updates from NETGEAR, as the company has released patches addressing the command injection flaw in versions 1.0.5.74 and later for affected R7850 models, and similar updates for other impacted device series. Network segmentation and access control measures can help limit the potential impact of exploitation by reducing the attack surface and preventing lateral movement within the network. Implementing strong authentication controls, including multi-factor authentication where possible, can reduce the likelihood of unauthorized access to device management interfaces. Security monitoring should include inspection of unusual network traffic patterns and system command execution logs that might indicate exploitation attempts. The vulnerability aligns with ATT&CK technique T1059.001 for command and scripting interpreter, where adversaries use legitimate system tools to execute commands, and T1068 for exploit for privilege escalation, as the initial compromise typically occurs through authenticated access followed by privilege escalation through command injection. Organizations should also consider implementing network intrusion detection systems that can identify suspicious command execution patterns and regularly audit device configurations to ensure that unauthorized changes have not occurred.