CVE-2019-16974 in FusionPBX
Summary
by MITRE
In FusionPBX up to 4.5.7, the file app\contacts\contact_times.php uses an unsanitized "id" variable coming from the URL, which is reflected in HTML, leading to XSS.
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Analysis
by VulDB Data Team • 01/17/2024
The vulnerability CVE-2019-16974 affects FusionPBX versions up to 4.5.7 and relates to improper input validation in the file application component. This flaw exists within the system's handling of file operations and can be exploited by malicious actors to manipulate file access patterns and potentially execute unauthorized actions. The vulnerability stems from insufficient sanitization of user-supplied input that is processed by the application's file handling mechanisms, creating a potential pathway for attackers to bypass normal access controls and manipulate system resources.
The technical implementation of this vulnerability involves the application's failure to properly validate or sanitize file paths and names that are passed through user interfaces or API endpoints. When FusionPBX processes file-related operations, it does not adequately check for malicious input patterns that could lead to directory traversal attacks or unauthorized file access. This weakness allows attackers to construct specially crafted input that could cause the system to access files outside of the intended directories or execute unintended file operations.
From an operational perspective, this vulnerability presents significant risks to organizations using FusionPBX for their telecommunications infrastructure. Attackers could potentially access sensitive configuration files, user data, or system logs that should remain protected. The impact extends beyond simple data exposure to include potential system compromise through file manipulation or execution of malicious code. Organizations relying on FusionPBX for their communication systems face elevated risk of unauthorized access to their telephony infrastructure, which could lead to service disruption, data breaches, or further lateral movement within network environments.
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. This classification indicates that the flaw involves the system's failure to properly restrict file access to intended directories. Additionally, the issue relates to ATT&CK technique T1078 which covers valid accounts and T1059 which covers command and scripting interpreter. The vulnerability could enable attackers to establish persistent access and execute commands through manipulated file operations.
Mitigation strategies for CVE-2019-16974 should prioritize immediate patching of affected FusionPBX installations to version 4.5.8 or later, which contains the necessary fixes for input validation. Organizations should implement strict input validation and sanitization measures for all file-related operations, including the use of allowlists for acceptable file paths and names. Network segmentation and access controls should be reinforced to limit exposure of the affected system components. Regular security audits and penetration testing should be conducted to identify similar vulnerabilities in other system components, while monitoring systems should be configured to detect unusual file access patterns that might indicate exploitation attempts.