CVE-2020-3293 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-2020-3293 affects Cisco Small Business routers including the RV320 and RV325 Series as well as the RV016 RV042 and RV082 models. These devices operate within small business environments where they serve as critical network infrastructure components managing traffic flow and providing security services. The vulnerability resides in the web-based management interface which represents a common attack surface for network devices since it provides a user-friendly method for administrators to configure and monitor device settings. This interface becomes particularly dangerous when compromised since it grants access to the underlying operating system with elevated privileges.
The technical flaw stems from inadequate input validation mechanisms within the web-based management interface scripts. Specifically the vulnerability manifests as insufficient boundary checks on user-supplied data, allowing attackers to submit overly large values that exceed the allocated stack space. This weakness directly maps to CWE-121 Stack-based Buffer Overflow which occurs when a program writes data beyond the boundaries of a fixed-length stack buffer. The vulnerability is classified as a stack overflow condition because the malicious input causes the program to write beyond the allocated memory space, potentially corrupting adjacent memory locations including return addresses and control data. This type of vulnerability is particularly dangerous because it can be exploited to overwrite critical program execution flow.
The operational impact of this vulnerability is severe as it allows authenticated attackers with administrative privileges to execute arbitrary code with root privileges on the underlying operating system. The attack requires only administrative login credentials which are often obtained through social engineering, credential theft, or weak password policies rather than complex initial access vectors. Once exploited, the attacker can cause the device to crash or gain complete control over the router's operations, potentially leading to network disruption, data exfiltration, or use as a pivot point for further attacks within the network. The ability to execute code with root privileges means attackers can modify firmware, establish backdoors, or redirect network traffic without detection.
Mitigation strategies should focus on immediate patch application from Cisco which addresses the input validation issues in the web interface scripts. Network administrators should also implement network segmentation to limit access to administrative interfaces and enforce strong authentication mechanisms including multi-factor authentication. Regular security audits of network device configurations should be conducted to identify and remove unnecessary administrative accounts. The vulnerability aligns with ATT&CK technique T1059 Command and Scripting Interpreter which describes how adversaries use legitimate system utilities to execute commands and scripts. Organizations should also consider implementing network monitoring solutions that can detect anomalous traffic patterns indicative of exploitation attempts. The affected devices should be configured to disable unnecessary services and restrict administrative access to trusted network segments only. Additionally, security awareness training for administrators should emphasize the importance of credential protection and regular password rotation to prevent unauthorized access to administrative interfaces.