CVE-2021-45626 in RBK20
Summary
by MITRE • 12/26/2021
Certain NETGEAR devices are affected by command injection by an unauthenticated attacker. This affects RBK20 before 2.6.1.36, RBR20 before 2.6.1.36, RBS20 before 2.6.1.38, RBK40 before 2.6.1.36, RBR40 before 2.6.1.36, RBS40 before 2.6.1.38, RBK50 before 2.6.1.40, RBR50 before 2.6.1.40, RBS50 before 2.6.1.40, and RBS50Y before 2.6.1.40.
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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 issue stems from insufficient input validation and sanitization within the device's web interface handling routines, creating a pathway for remote code execution without requiring authentication credentials. The affected models span multiple RBK and RBR series devices, indicating a widespread vulnerability across NETGEAR's product line that impacts both consumer and small business networking gear. This type of vulnerability fundamentally compromises the device's integrity and can lead to complete system compromise, making it particularly dangerous in networked environments where such devices serve as core infrastructure components.
The technical implementation of this command injection vulnerability occurs through improper handling of user-supplied input in web-based administrative interfaces. Attackers can craft malicious payloads that bypass authentication mechanisms and directly execute system commands on the affected devices. This flaw typically manifests when the device fails to properly sanitize or escape input parameters before processing them, allowing attackers to inject shell commands that get executed with the privileges of the web server process. The vulnerability affects specific firmware versions across multiple device models, with the affected versions being prior to the listed patch releases, suggesting that the issue was introduced in firmware versions that were widely deployed and potentially used in production environments without adequate security testing.
The operational impact of this vulnerability extends far beyond simple unauthorized access, as successful exploitation can result in complete network compromise and persistent backdoor access. An attacker who successfully exploits this vulnerability can gain full control over the affected networking device, potentially using it as a pivot point to attack other systems within the network. The unauthenticated nature of this vulnerability means that attackers do not need to know valid credentials to exploit the flaw, making it particularly dangerous for devices that are exposed to the internet. This vulnerability can be leveraged to establish persistent access, modify network configurations, redirect traffic, or even use the compromised device as a launching point for further attacks against other networked systems, creating a significant risk for organizations that rely on these devices for network infrastructure.
Mitigation strategies for this vulnerability should focus on immediate firmware updates provided by NETGEAR, which address the input validation issues that enable the command injection. Organizations should prioritize patching all affected devices with the latest firmware versions that contain the necessary security fixes. Network segmentation and firewall rules should be implemented to limit direct internet access to these devices, reducing the attack surface. Additionally, monitoring network traffic for suspicious command execution patterns and implementing intrusion detection systems can help identify potential exploitation attempts. The vulnerability aligns with CWE-77 and CWE-88 categories related to command injection and improper input sanitization, and can be mapped to ATT&CK techniques such as T1059 for command and script injection, and T1021 for remote services. Regular security assessments and vulnerability scanning should be conducted to identify similar issues in other network infrastructure components and ensure comprehensive protection against similar attack vectors.