CVE-2020-3290 in RV016
Summary
by MITRE
Multiple vulnerabilities in the web-based management interface of Cisco Small Business RV320 and RV325 Series Routers and Cisco Small Business RV016, RV042, and RV082 Routers could allow an authenticated, remote attacker with administrative privileges to execute arbitrary code on an affected device. The vulnerabilities are due to insufficient boundary restrictions on user-supplied input to scripts in the web-based management interface. An attacker with administrative privileges that are sufficient to log in to the web-based management interface could exploit each vulnerability by sending crafted requests that contain overly large values to an affected device, causing a stack overflow. A successful exploit could allow the attacker to cause the device to crash or allow the attacker to execute arbitrary code with root privileges on the underlying operating system.
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Analysis
by VulDB Data Team • 10/25/2020
The vulnerability identified as CVE-2020-3290 affects Cisco Small Business routers including the RV320 and RV325 series models along with RV016, RV042, and RV082 devices. These routers are commonly deployed in small business environments where they serve as network gateways and provide essential connectivity services. The vulnerability resides within the web-based management interface, which represents a critical attack surface since it provides administrative access to the device configuration and operational parameters. This interface typically allows network administrators to configure routing policies, firewall rules, and other security settings that control network traffic flow.
The technical flaw stems from insufficient input validation and boundary checking mechanisms within the web interface scripts. Specifically, the vulnerability occurs when the system fails to properly validate the size and content of user-supplied data passed to internal processing functions. This weakness creates an opportunity for stack overflow conditions when maliciously crafted requests containing oversized parameters are submitted to the affected device. The insufficient boundary restrictions represent a classic software security flaw that falls under the CWE-129 category of "Improper Validation of Array Index" and more broadly aligns with CWE-787 "Out-of-bounds Write" which is commonly exploited in buffer overflow scenarios. The vulnerability is particularly dangerous because it requires only administrative authentication, which is often already present in business environments where routers are configured by network administrators.
The operational impact of this vulnerability is severe and potentially catastrophic for affected organizations. An attacker with administrative credentials can exploit this vulnerability to execute arbitrary code with root privileges on the underlying operating system, effectively gaining complete control over the router. This level of access enables the attacker to manipulate network traffic, redirect connections to malicious servers, disable security features, and establish persistent backdoors for future access. The ability to cause the device to crash also represents a denial of service risk that could disrupt critical business operations, particularly in environments where these routers serve as primary network gateways. The vulnerability's remote exploitation capability means that attackers do not need physical access to the device, making it particularly attractive for cybercriminals who can target multiple devices simultaneously from external networks.
Organizations should implement immediate mitigations including applying the latest security patches from Cisco, which address the input validation issues in the web interface scripts. Network segmentation and access control measures should be strengthened to limit administrative access to only authorized personnel with legitimate business needs. The principle of least privilege should be enforced by ensuring that administrative accounts have the minimum necessary permissions and that multi-factor authentication is implemented where possible. Monitoring and logging of administrative activities should be enhanced to detect suspicious access patterns or unusual parameter values being submitted to the web interface. Additionally, network administrators should consider disabling the web management interface when not actively needed and instead rely on secure command-line interfaces or dedicated management protocols. The vulnerability demonstrates the importance of input validation in web applications and aligns with ATT&CK technique T1059.007 "Command and Scripting Interpreter: PowerShell" and T1068 "Exploitation for Privilege Escalation" which highlight how boundary condition flaws can be exploited to gain elevated system privileges and execute arbitrary code in network infrastructure devices.