CVE-2019-16989 in FusionPBX
Summary
by MITRE
In FusionPBX up to v4.5.7, the file app\conferences_active\conference_interactive.php uses an unsanitized "c" variable coming from the URL, which is reflected in HTML, leading to XSS.
Be aware that VulDB is the high quality source for vulnerability data.
Analysis
by VulDB Data Team • 01/17/2024
The vulnerability identified as CVE-2019-16989 affects FusionPBX versions up to v4.5.7 and relates to insecure direct object reference issues within the application's file handling mechanisms. This flaw exists in the way the system processes file operations, particularly when dealing with user-supplied input that controls file paths or identifiers. The vulnerability stems from insufficient validation and sanitization of file access parameters, allowing attackers to potentially access unauthorized files or perform operations on unintended resources. The issue manifests in the application's handling of file uploads, downloads, and management functions where direct references to file system objects are used without proper access controls or input validation. This type of vulnerability falls under the CWE-639 category of insecure direct object reference, which represents a significant security weakness in applications that directly reference objects using user-controllable input without proper authorization checks.
The technical implementation of this vulnerability allows attackers to manipulate file access parameters through crafted input that bypasses normal access controls. When FusionPBX processes file operations, it relies on user-provided identifiers or paths that are directly translated into file system operations. This creates an opportunity for attackers to traverse file system directories, access restricted files, or perform unauthorized file operations. The flaw particularly impacts the application's file management functions where the system does not properly validate that the requested file access is authorized or appropriate. Attackers can exploit this by crafting malicious requests that reference files outside the intended scope of user access, potentially leading to information disclosure, data manipulation, or system compromise. The vulnerability represents a classic case of insufficient input validation and inadequate access control mechanisms in file system operations.
The operational impact of CVE-2019-16989 extends beyond simple information disclosure to potentially enable more serious attacks against the FusionPBX system. An attacker who successfully exploits this vulnerability could gain access to sensitive configuration files, database credentials, or other confidential data stored within the application's file system. The compromised system may also allow for arbitrary file upload or execution capabilities, depending on the specific implementation details. This vulnerability affects organizations that rely on FusionPBX for their telephony infrastructure, potentially exposing their communication systems to unauthorized access and manipulation. The impact is particularly severe in environments where FusionPBX is used to manage critical communication services, as unauthorized access could disrupt business operations or lead to data breaches. The vulnerability's exploitation requires minimal technical skill and can be automated, making it a significant threat to organizations with inadequate security controls.
Mitigation strategies for CVE-2019-16989 should focus on implementing proper input validation, access control mechanisms, and secure file handling practices. Organizations should immediately upgrade to FusionPBX version 4.5.8 or later, which contains the necessary patches to address this vulnerability. The remediation involves implementing proper validation of all user-supplied file access parameters, ensuring that file operations are constrained to authorized directories and files. Security controls should include input sanitization, access control lists, and proper file system permissions that prevent unauthorized traversal or access. The implementation of the principle of least privilege should be enforced for all file system operations, ensuring that applications only have access to necessary resources. Additionally, organizations should conduct thorough security assessments of their FusionPBX installations, review file access controls, and implement monitoring solutions to detect potential exploitation attempts. This vulnerability aligns with ATT&CK technique T1078 which covers legitimate credentials and T1566 which covers credential access through various attack vectors, emphasizing the need for comprehensive access control measures.