CVE-2020-3289 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 CVE-2020-3289 vulnerability represents a critical security flaw in Cisco Small Business routers that affects the RV320 and RV325 Series devices along with the RV016, RV042, and RV082 models. This vulnerability exists within the web-based management interface of these networking devices, creating a pathway for authenticated remote code execution that could compromise the entire network infrastructure. The flaw stems from inadequate input validation mechanisms that fail to properly restrict user-supplied data submitted to backend scripts, creating a dangerous attack surface for malicious actors who possess administrative credentials.
The technical exploitation of this vulnerability relies on a stack overflow condition that occurs when crafted requests containing excessively large values are sent to the affected devices. This type of vulnerability falls under the CWE-121 category of stack-based buffer overflow, where insufficient boundary checks on input data allow attackers to overwrite adjacent memory locations in the program stack. The attack vector requires an authenticated attacker with administrative privileges, but once achieved, the exploitation can lead to complete system compromise through the execution of arbitrary code with root privileges. The underlying operating system of these routers is vulnerable to this attack because the web interface scripts do not properly validate the size or content of user inputs before processing them.
The operational impact of CVE-2020-3289 extends far beyond simple device instability, as successful exploitation could result in complete network compromise and persistent backdoor access. An attacker who successfully exploits this vulnerability could gain root-level access to the router's operating system, allowing them to modify network configurations, redirect traffic, or establish persistent access points within the network infrastructure. This vulnerability directly aligns with ATT&CK technique T1059.007 for command and scripting interpreter and T1068 for exploit for privilege escalation, enabling attackers to maintain persistent access and escalate their privileges within the compromised network environment. The vulnerability affects the availability and integrity of network services, potentially causing service disruptions and creating opportunities for advanced persistent threats to establish long-term network presence.
Organizations should implement immediate mitigation strategies including applying Cisco's security patches and updates to address the identified input validation flaws in the web interface components. Network segmentation and access control measures should be strengthened to limit administrative access to only authorized personnel, while monitoring systems should be deployed to detect anomalous traffic patterns that might indicate exploitation attempts. The vulnerability demonstrates the importance of proper input validation and boundary checking in web applications, reinforcing industry best practices outlined in standards such as the OWASP Top Ten and NIST cybersecurity guidelines. Regular security assessments and vulnerability scanning of network infrastructure should be conducted to identify similar input validation weaknesses that could lead to similar exploitation scenarios across the organization's IT assets.