CVE-2023-20161 in Small Business Series Switch
Summary
by MITRE • 05/18/2023
Multiple vulnerabilities in the web-based user interface of certain Cisco Small Business Series Switches could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition or execute arbitrary code with root privileges on an affected device. These vulnerabilities are due to improper validation of requests that are sent to the web interface. For more information about these vulnerabilities, see the Details section of this advisory.
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Analysis
by VulDB Data Team • 08/25/2025
Cisco Small Business Series Switches are widely deployed in enterprise environments where they serve as critical network infrastructure components managing traffic flow and connectivity for numerous devices. These switches typically operate with web-based management interfaces that allow administrators to configure and monitor network operations remotely. The vulnerabilities present in these devices represent a significant risk to network security and operational continuity due to their potential for remote exploitation without authentication requirements.
The technical flaw stems from inadequate input validation mechanisms within the web-based user interface of affected Cisco Small Business Series Switches. When requests are sent to the web interface, the system fails to properly validate the structure and content of these requests before processing them. This improper validation creates multiple pathways for exploitation where an attacker can craft malicious inputs that bypass normal security checks. The vulnerability architecture allows for both denial of service conditions and arbitrary code execution with root privileges, indicating a fundamental flaw in the request handling and input processing logic of the web interface components.
Operational impact of these vulnerabilities extends beyond simple service disruption to encompass complete system compromise. An unauthenticated remote attacker can leverage these weaknesses to either render the switch inoperable through denial of service attacks or to gain full administrative control of the device. The ability to execute arbitrary code with root privileges means that attackers can install malicious software, modify network configurations, access sensitive data, or establish persistent backdoors within the network infrastructure. This represents a critical escalation from simple DoS conditions to full system compromise that could affect entire network segments.
The vulnerability landscape for these switches aligns with common weakness enumerations such as CWE-20, which describes improper input validation, and CWE-77, which covers command injection. From an adversary perspective, this vulnerability maps to several ATT&CK techniques including T1210 for exploitation of remote services and T1059 for command and scripting interpreters. The attack surface is particularly concerning given that these switches are often deployed in environments where network management interfaces are accessible from untrusted networks, and the lack of authentication requirements eliminates the need for preliminary reconnaissance or credential harvesting.
Mitigation strategies should include immediate deployment of available Cisco security patches and firmware updates that address the input validation flaws in the web interface components. Network segmentation should be implemented to isolate switch management interfaces from untrusted network segments, while access control lists can be configured to restrict management interface access to known good IP addresses only. Additional protective measures include disabling unnecessary web interface services when not required, implementing strong network monitoring to detect anomalous traffic patterns, and maintaining detailed audit logs of all management interface activity for security analysis and incident response purposes. Organizations should also consider implementing network access control solutions and regular vulnerability scanning to identify and remediate similar issues across their network infrastructure.