CVE-2008-6894 in Phone System
Summary
by MITRE
Multiple cross-site scripting (XSS) vulnerabilities in login.php in 3CX Phone System Free Edition 6.1793 and 6.0.806.0 allow remote attackers to inject arbitrary web script or HTML via the (1) fName and (2) fPassword parameters.
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Analysis
by VulDB Data Team • 08/13/2021
The vulnerability identified as CVE-2008-6894 represents a critical cross-site scripting flaw within the 3CX Phone System Free Edition versions 6.1793 and 6.0.806.0. This issue affects the login.php script which serves as the primary authentication interface for the telephony system, making it a prime target for malicious actors seeking unauthorized access to communication infrastructure. The vulnerability stems from inadequate input validation and output encoding mechanisms that fail to properly sanitize user-supplied data before processing or displaying it within the web interface.
The technical implementation of this vulnerability occurs through two specific parameters named fName and fPassword within the login.php script. Attackers can exploit these entry points by injecting malicious JavaScript code or HTML content through the username and password fields during the login process. When the system processes these parameters without proper sanitization, the injected code gets executed within the context of other users' browsers who subsequently access the vulnerable application. This creates a persistent threat vector that can be leveraged for session hijacking, credential theft, or redirection to malicious websites. The flaw operates under CWE-79 which categorizes cross-site scripting vulnerabilities as weaknesses in input validation and output encoding, specifically targeting the failure to properly escape or filter user-controllable data.
The operational impact of this vulnerability extends beyond simple data theft, as it provides attackers with the capability to manipulate the authentication process and potentially gain unauthorized access to the entire 3CX phone system infrastructure. Organizations utilizing these vulnerable versions face significant risks including unauthorized phone system access, potential disruption of critical communication services, and exposure of sensitive business communications. The attack surface is particularly concerning given that the vulnerability exists in the login interface, meaning any attempt to authenticate could serve as an entry point for more sophisticated attacks. The vulnerability also aligns with ATT&CK technique T1190 which describes the use of web application vulnerabilities for initial access, and T1566 which covers social engineering through malicious web content.
Mitigation strategies for this vulnerability require immediate patching of the affected 3CX Phone System versions to the latest available releases that contain proper input validation and output encoding fixes. Organizations should implement comprehensive input sanitization measures that filter and escape all user-controllable data before processing, particularly focusing on the specific parameters mentioned in the vulnerability description. Network segmentation and web application firewalls can provide additional layers of protection by monitoring and filtering malicious traffic patterns associated with XSS attacks. Regular security assessments and penetration testing should be conducted to identify similar vulnerabilities within the telephony infrastructure, while security awareness training for system administrators can help prevent exploitation through social engineering approaches. The remediation process should also include monitoring for any suspicious authentication attempts or unusual network activity that might indicate exploitation attempts against the vulnerable system.