CVE-2017-15359 in Phone System
Summary
by MITRE
In the 3CX Phone System 15.5.3554.1, the Management Console typically listens to port 5001 and is prone to a directory traversal attack: "/api/RecordingList/DownloadRecord?file=" and "/api/SupportInfo?file=" are the vulnerable parameters. An attacker must be authenticated to exploit this issue to access sensitive information to aid in subsequent attacks.
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Analysis
by VulDB Data Team • 01/02/2025
The CVE-2017-15359 vulnerability affects the 3CX Phone System version 15.5.3554.1 management console which operates on port 5001 and exposes two specific API endpoints susceptible to directory traversal attacks. This vulnerability resides in the file parameter handling within the RecordingList/DownloadRecord and SupportInfo API endpoints, creating a path traversal condition that allows unauthorized file access. The flaw stems from inadequate input validation and sanitization of user-supplied file paths, enabling attackers to manipulate the file parameter to access arbitrary files on the server filesystem.
The technical implementation of this vulnerability involves the management console failing to properly validate or sanitize the file parameter input before processing file system operations. When an attacker crafts malicious requests containing directory traversal sequences such as ../ or ..\ in the file parameter, the system processes these requests without sufficient validation, allowing access to files outside the intended directory structure. This weakness creates a direct path to sensitive information including system logs, configuration files, and potentially user data that should remain protected within the application's restricted access zones.
The operational impact of this vulnerability is significant as it provides attackers with a means to escalate privileges and gather intelligence for more sophisticated attacks. Although authentication is required to exploit this vulnerability, it represents a critical information disclosure risk that can provide attackers with system insights, configuration details, and potentially sensitive data that could aid in privilege escalation or further exploitation attempts. The vulnerability essentially creates an information leakage channel that can expose internal system structures and potentially sensitive operational data.
This 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. From an ATT&CK framework perspective, this weakness maps to T1083 (File and Directory Discovery) and T1566 (Phishing for Information) as it enables attackers to discover and extract sensitive files from the system. The vulnerability also relates to T1005 (Data from Local System) and T1059 (Command and Scripting Interpreter) as it can provide access to system files that might be used to further compromise the system.
Organizations should implement immediate mitigations including input validation and sanitization of all user-supplied parameters, particularly file paths, through the implementation of strict whitelist validation for file access operations. The management console should be configured to use absolute paths with strict access controls and proper file system permissions. Additionally, network segmentation should be implemented to restrict access to port 5001 to authorized administrative networks only. Regular security audits and penetration testing should be conducted to identify similar path traversal vulnerabilities in other system components. The 3CX vendor released patches and updates addressing this specific vulnerability, and organizations should ensure immediate deployment of these security updates to remediate the identified weakness.