CVE-2019-19552 in FreePBX
Summary
by MITRE
In userman 13.0.76.43 through 15.0.20 in Sangoma FreePBX, XSS exists in the user management screen of the Administrator web site, i.e., the/admin/config.php?display=userman URI. An attacker with sufficient privileges can edit the Display Name of a user and embed malicious XSS code. When another user (such as an admin) visits the main User Management screen, the XSS payload will render and execute in the context of the victim user's account.
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Analysis
by VulDB Data Team • 03/07/2024
The vulnerability CVE-2019-19552 represents a cross-site scripting flaw within the user management functionality of Sangoma FreePBX versions ranging from 13.0.76.43 through 15.0.20. This issue specifically affects the administrative web interface at the /admin/config.php?display=userman URI, where user management operations are conducted. The vulnerability stems from insufficient input validation and output encoding mechanisms that fail to properly sanitize user-supplied data before rendering it within the web application's user interface. This particular implementation flaw allows attackers to inject malicious script code into the Display Name field of user accounts, creating a persistent XSS vector that can be exploited across multiple user sessions.
The technical exploitation of this vulnerability requires an attacker to possess sufficient privileges to modify user account information within the FreePBX administrative interface. Once the malicious payload is embedded into a user's Display Name field, the XSS attack becomes persistent and can be triggered whenever any user, particularly administrators, navigate to the main User Management screen. The execution context of the malicious code occurs within the victim user's browser session, effectively allowing the attacker to operate with the privileges and permissions of the compromised user account. This vulnerability falls under CWE-79 - Improper Neutralization of Input During Web Page Generation, which specifically addresses the failure to properly encode or escape user-controllable data before including it in web output. The attack vector aligns with ATT&CK technique T1059.007 - Command and Scripting Interpreter: JavaScript, as it leverages JavaScript execution within the browser context to perform malicious activities.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to escalate privileges, steal session cookies, perform unauthorized actions within the application, or even redirect victims to malicious websites. When administrators view the user management screen, their browsers execute the injected JavaScript code, potentially allowing attackers to access sensitive administrative functions, modify user permissions, or extract confidential information from the application. The persistent nature of this XSS vulnerability means that the malicious payload remains active until manually removed from the database, creating an ongoing threat vector that can affect multiple users over extended periods. Organizations running affected FreePBX versions face significant security risks, as the vulnerability can be exploited to gain unauthorized access to critical telephony infrastructure management functions and potentially compromise the entire communication system.
Mitigation strategies for CVE-2019-19552 should focus on immediate patch application to the affected FreePBX versions, as well as implementing additional security controls to prevent unauthorized access to administrative functions. Organizations should ensure that all users with administrative privileges undergo proper authentication and authorization procedures, and that privilege levels are strictly enforced through role-based access controls. Input validation and output encoding mechanisms should be strengthened to prevent any user-controllable data from being rendered without proper sanitization, particularly within web application interfaces that display user-generated content. Network segmentation and monitoring solutions should be deployed to detect anomalous behavior patterns that might indicate exploitation attempts. Additionally, regular security audits and penetration testing should be conducted to identify and remediate similar vulnerabilities across the entire telephony infrastructure ecosystem. The vulnerability demonstrates the critical importance of implementing defense-in-depth strategies and maintaining up-to-date security patches across all components of unified communications platforms.