CVE-2017-16565 in HT802
Summary
by MITRE
Cross-Site Request Forgery (CSRF) in /cgi-bin/login on Vonage (Grandstream) HT802 devices allows attackers to authenticate a user via the login screen using the default password of 123 and submit arbitrary requests.
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Analysis
by VulDB Data Team • 12/04/2019
The vulnerability CVE-2017-16565 represents a critical cross-site request forgery flaw discovered in Vonage Grandstream HT802 devices that fundamentally compromises the authentication security model of these VoIP endpoints. This vulnerability exists within the web-based administrative interface accessible through the /cgi-bin/login endpoint, where attackers can exploit the CSRF mechanism to bypass normal authentication procedures. The flaw specifically targets the device's default credential handling, allowing unauthorized parties to authenticate using the well-known default password of 123, which remains unchanged in many deployments despite security warnings.
The technical implementation of this vulnerability stems from the absence of proper anti-CSRF tokens or validation mechanisms within the authentication flow of the Grandstream HT802 device. When a user accesses the login page, the device fails to implement sufficient protections against forged requests that could be submitted from malicious web pages or compromised networks. This weakness enables attackers to craft malicious requests that, when executed by an authenticated user, can perform administrative actions without proper authorization. The vulnerability operates at the application layer and affects the device's web interface security controls, making it particularly dangerous as it can be exploited remotely without requiring physical access or advanced technical skills.
The operational impact of this vulnerability extends beyond simple unauthorized access, as it provides attackers with the ability to submit arbitrary requests to the device's administrative interface. This capability allows for complete compromise of the device's configuration, enabling attackers to modify voicemail settings, change phone numbers, alter SIP configuration parameters, and potentially redirect calls to malicious destinations. The default password of 123 creates an additional attack vector that significantly lowers the barrier to exploitation, as many administrators fail to change these default credentials even after initial deployment. This vulnerability directly violates security principles outlined in the OWASP Top Ten, specifically addressing the lack of proper authentication and session management controls.
The exploitation of this vulnerability aligns with several tactics described in the MITRE ATT&CK framework, particularly those related to credential access and privilege escalation. Attackers can leverage this flaw to establish persistent access to the VoIP infrastructure, potentially using the compromised device as a foothold for broader network attacks. The vulnerability also demonstrates poor security implementation practices that correlate with CWE-352, which defines cross-site request forgery vulnerabilities, and CWE-798, which addresses the use of hard-coded credentials in software. Organizations utilizing these devices face significant risk of unauthorized call routing, eavesdropping, and potential use as a pivot point for attacks against other network components.
Mitigation strategies for CVE-2017-16565 require immediate action including changing the default password to a strong, unique credential, implementing proper anti-CSRF token validation mechanisms, and restricting access to the device's administrative interface through network segmentation. Network administrators should also consider disabling the web interface entirely if it is not required for management purposes, and implement proper firewall rules to limit access to the device's administrative ports from trusted networks only. Regular security audits and firmware updates are essential to address this vulnerability, as the affected devices require firmware patches to properly implement CSRF protection mechanisms and remove the default credential exposure. Organizations should also implement monitoring solutions to detect unauthorized access attempts and configuration changes to these devices.