CVE-2021-38527 in CBR40
Summary
by MITRE • 08/11/2021
Certain NETGEAR devices are affected by command injection by an unauthenticated attacker. This affects CBR40 before 2.5.0.14, EX6100v2 before 1.0.1.98, EX6150v2 before 1.0.1.98, EX6250 before 1.0.0.132, EX6400 before 1.0.2.158, EX6400v2 before 1.0.0.132, EX6410 before 1.0.0.132, EX6420 before 1.0.0.132, EX7300 before 1.0.2.158, EX7300v2 before 1.0.0.132, EX7320 before 1.0.0.132, EX7700 before 1.0.0.216, EX8000 before 1.0.1.232, R7800 before 1.0.2.78, RBK12 before 2.6.1.44, RBR10 before 2.6.1.44, RBS10 before 2.6.1.44, RBK20 before 2.6.1.38, RBR20 before 2.6.1.36, RBS20 before 2.6.1.38, RBK40 before 2.6.1.38, 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, 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, RBS850 before 3.2.16.6, RBS40V before 2.6.2.4, RBS50Y before 2.6.1.40, RBW30 before 2.6.2.2, and XR500 before 2.3.2.114.
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Analysis
by VulDB Data Team • 08/16/2021
This vulnerability represents a critical command injection flaw in NETGEAR networking equipment that allows unauthenticated remote attackers to execute arbitrary commands on affected devices. The vulnerability stems from insufficient input validation within the web interface of these routers and access points, creating a pathway for malicious actors to inject and execute system commands without requiring any authentication credentials. The affected devices span multiple product lines including CBR40, EX series routers, R7800, and various RBK, RBR, RBS, and XR series devices, indicating a widespread issue across NETGEAR's networking portfolio. This flaw operates at the application layer and can be exploited through web-based interfaces, making it particularly dangerous as it requires no prior access to the network or device credentials.
The technical implementation of this vulnerability involves the improper handling of user-supplied input parameters that are directly passed to system commands without adequate sanitization or validation. Attackers can craft malicious requests containing command injection payloads that get executed by the underlying operating system, potentially allowing complete system compromise. The vulnerability is classified under CWE-77 as Command Injection, which is a well-documented weakness in software systems where user input is improperly handled in command execution contexts. This type of vulnerability enables attackers to perform actions such as modifying device configurations, accessing sensitive data, creating backdoors, or even taking complete control of the affected network infrastructure.
The operational impact of this vulnerability is severe as it provides attackers with unrestricted access to affected NETGEAR devices, potentially enabling them to compromise entire networks. An unauthenticated attacker could exploit this vulnerability from outside the network perimeter, making it particularly dangerous for enterprise and home users alike. The compromised devices could serve as entry points for further attacks, allowing attackers to pivot within the network and target other connected systems. This vulnerability could also enable attackers to modify network configurations, redirect traffic, or establish persistent access points within the network infrastructure. The widespread nature of affected devices means that numerous network endpoints could be compromised simultaneously, potentially affecting thousands of users across different geographical locations and network environments.
Mitigation strategies should include immediate firmware updates from NETGEAR to address the command injection vulnerability, as these updates typically contain patches that properly validate and sanitize input parameters before they are processed by system commands. Network administrators should also implement network segmentation and access controls to limit the potential impact of a compromised device, ensuring that even if one device is compromised, attackers cannot easily move laterally through the network. Additionally, monitoring network traffic for suspicious command execution patterns and implementing intrusion detection systems can help identify exploitation attempts. Organizations should also consider disabling unnecessary web interfaces and services on network devices, reducing the attack surface available to potential attackers. The vulnerability aligns with ATT&CK technique T1059.001 for Command and Scripting Interpreter, as attackers can leverage this flaw to execute commands directly on the affected systems, potentially leading to privilege escalation and persistent access within the network environment.