CVE-2006-5038 in Ss28s Wifi Voip Sip Skype Phone
Summary
by MITRE
The FiWin SS28S WiFi VoIP SIP/Skype Phone, firmware version 01_02_07, has a hard-coded username and password, which allows remote attackers to gain administrative access via telnet.
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Analysis
by VulDB Data Team • 04/09/2025
The FiWin SS28S WiFi VoIP SIP/Skype Phone represents a critical security vulnerability classified as CVE-2006-5038, where the device firmware version 01_02_07 contains hard-coded authentication credentials that persist across all device instances. This flaw constitutes a fundamental design weakness that directly violates security best practices and industry standards such as those outlined in CWE-259, which specifically addresses the use of hard-coded passwords. The vulnerability exists at the firmware level where developers embedded default administrative credentials directly into the codebase, creating a persistent backdoor that remains unchanged regardless of device deployment or configuration.
The technical implementation of this vulnerability allows remote attackers to exploit the device through the telnet protocol, which remains enabled and accessible without proper authentication mechanisms. The hard-coded credentials provide immediate administrative access to the device's command-line interface, enabling attackers to execute arbitrary commands, modify device configurations, and potentially gain control over the entire VoIP communication infrastructure. This represents a classic case of insecure default configuration as detailed in the MITRE ATT&CK framework under the technique of T1078.004, which covers legitimate credentials and default passwords as entry points for unauthorized access.
The operational impact of this vulnerability extends beyond simple unauthorized access, as the compromised device can serve as a pivot point for broader network attacks within enterprise VoIP infrastructures. Attackers can leverage the administrative access to manipulate call routing, intercept communications, or establish persistent access points for further network exploration. The vulnerability affects not only individual devices but also poses risks to entire communication networks, particularly in environments where multiple VoIP devices share similar default configurations. Organizations deploying these devices face significant risk exposure, as the hard-coded credentials remain unchanged even after device reboots or firmware updates, creating a persistent threat vector that can be exploited repeatedly.
Mitigation strategies for this vulnerability require immediate action including disabling telnet services when not actively needed, implementing network segmentation to isolate VoIP devices, and establishing robust monitoring for unauthorized access attempts. Security teams should conduct comprehensive inventory audits to identify all affected devices and ensure that default credentials are changed immediately upon discovery. The vulnerability highlights the importance of secure development practices and proper authentication mechanisms as outlined in the OWASP Top Ten and NIST Cybersecurity Framework. Organizations must also implement network access controls and regular security assessments to prevent similar issues in future deployments, as this vulnerability demonstrates the critical need for proper credential management and secure configuration practices in networked devices.