CVE-2018-7654 in 3CX
Summary
by MITRE
On 3CX 15.5.6354.2 devices, the parameter "file" in the request "/api/RecordingList/download?file=" allows full access to files on the server via path traversal.
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Analysis
by VulDB Data Team • 01/10/2020
The vulnerability identified as CVE-2018-7654 affects 3CX Phone System versions 15.5.6354.2 and potentially earlier releases, presenting a critical path traversal flaw within the application's recording download functionality. This security weakness resides in the API endpoint specifically designed for downloading recorded files, where the parameter named "file" fails to properly validate or sanitize user-supplied input. The flaw enables unauthorized access to sensitive files stored on the server by allowing attackers to manipulate the file parameter through directory traversal sequences such as "../" or similar constructs. The vulnerability directly impacts the confidentiality and integrity of the system by potentially exposing audio recordings, configuration files, or other sensitive data that should remain restricted to authorized personnel only.
The technical implementation of this vulnerability stems from inadequate input validation within the 3CX application's file handling mechanism. When the system processes the file parameter in the request path "/api/RecordingList/download?file=", it fails to implement proper sanitization or access control measures that would prevent traversal beyond the intended directory structure. This allows an attacker to craft malicious requests that navigate through the file system hierarchy, potentially accessing files outside the designated recording directory. The vulnerability aligns with CWE-22, which describes improper limitation of a pathname to a restricted directory, commonly known as path traversal or directory traversal attacks. The flaw represents a fundamental failure in input validation and access control implementation, creating an exploitable condition that directly violates the principle of least privilege.
The operational impact of this vulnerability extends beyond simple unauthorized file access, as it creates potential for significant data breaches and system compromise. Attackers could potentially access not only audio recordings but also system configuration files, user credentials, or other sensitive information stored within the server's file system. This vulnerability could facilitate further attacks by providing attackers with information that might aid in privilege escalation or lateral movement within the network. The exposure of recording files could result in privacy violations and regulatory compliance issues, particularly in environments where audio recordings contain sensitive business or personal information. Additionally, the ability to access system files might enable attackers to gather intelligence about the system configuration, potentially leading to more sophisticated attacks. The vulnerability affects organizations using 3CX Phone System versions that have not been patched, creating a persistent security risk that could be exploited by both internal and external threat actors.
Organizations affected by this vulnerability should immediately implement mitigations including applying the vendor-provided security patches or updates that address the path traversal flaw in the 3CX application. Network segmentation and access control measures should be enforced to limit access to the vulnerable API endpoints, particularly restricting access to only authorized administrative users. Input validation should be strengthened at the application level to ensure all user-supplied parameters undergo proper sanitization before being processed. The implementation of web application firewalls or security monitoring solutions can help detect and prevent exploitation attempts targeting this specific vulnerability. Regular security assessments and penetration testing should be conducted to identify similar flaws in other application components, while maintaining up-to-date inventory of all 3CX installations to ensure comprehensive patch management across the organization. The vulnerability demonstrates the importance of proper input validation and access control implementation, aligning with ATT&CK technique T1078 which covers valid accounts and credential access, and T1566 which covers credential access through various attack vectors including path traversal vulnerabilities.