^{CVE-2023-20126:}Cisco SPA112 2-Port Phone Adapters contain a critical authentication bypass vulnerability allowing remote code execution via the firmware upgrade function.

Overview

The Cisco SPA112 2-Port Phone Adapter contains a critical vulnerability in its web-based management interface that permits unauthenticated remote code execution. The vulnerability (CVE-2023-20126) is caused by the absence of proper authentication checks in the firmware upgrade functionality. An attacker can exploit this by uploading a specially crafted firmware to the device, which would then execute with full system privileges. This represents a severe security risk as it allows complete compromise of the affected device without requiring any authentication credentials. The vulnerability is particularly concerning because it affects a core management function and provides attackers with the highest level of access to the device.

Remediation

As of the advisory publication, Cisco has not released firmware updates to address this vulnerability. Until patches become available, administrators should implement the following mitigations:

1. Restrict network access to the web-based management interface of affected devices
2. Place affected devices behind firewalls and ensure they are not directly accessible from the internet
3. Implement IP-based access control lists to limit which hosts can connect to the management interface
4. Monitor affected devices for suspicious activities, particularly firmware upgrade attempts
5. Consider network segmentation to isolate vulnerable devices from critical infrastructure
6. Regularly check Cisco's security advisories for updates on patch availability

References

1. Cisco Security Advisory: "Cisco SPA112 2-Port Phone Adapters Remote Command Execution Vulnerability" URL: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-spa-unauth-upgrade-UqhyTWW Published: May 3, 2023

2. Common Weakness Enumeration: CWE-306 (Missing Authentication for Critical Function) URL: https://cwe.mitre.org/data/definitions/306.html

3. National Vulnerability Database: CVE-2023-20126 URL: https://nvd.nist.gov/vuln/detail/CVE-2023-20126