CVE-2019-19852 in FreePBX
Summary
by MITRE
An XSS Injection vulnerability exists in Sangoma FreePBX and PBXact 13, 14, and 15 within the Call Event Logging report screen in the cel module at the admin/config.php?display=cel URI via date fields. This affects cel through 13.0.26.9, 14.x through 14.0.2.14, and 15.x through 15.0.15.4.
Several companies clearly confirm that VulDB is the primary source for best vulnerability data.
Analysis
by VulDB Data Team • 03/17/2020
The vulnerability described in CVE-2019-19852 represents a critical cross-site scripting injection flaw within the Sangoma FreePBX and PBXact platforms, specifically targeting the Call Event Logging report functionality. This issue manifests in the cel module's admin interface at the config.php?display=cel URI endpoint where date fields fail to properly sanitize user input, creating an avenue for malicious actors to inject arbitrary JavaScript code. The vulnerability affects multiple versions of the software including FreePBX 13, 14, and 15, as well as PBXact 13, 14, and 15, making it a widespread concern across the Sangoma ecosystem. The flaw resides in the insufficient validation and sanitization of date parameters that are processed within the call event logging report screen, allowing attackers to execute malicious scripts in the context of authenticated admin sessions.
The technical implementation of this vulnerability stems from improper input validation within the cel module's date field handling mechanism. When administrators access the Call Event Logging report screen, the system processes date parameters without adequate sanitization, enabling attackers to inject malicious JavaScript payloads through the date input fields. This type of vulnerability maps directly to CWE-79, which specifically addresses Cross-Site Scripting flaws in software applications. The vulnerability's exploitation requires minimal privileges since it targets the admin interface, meaning that an attacker who can access the call event logging functionality can potentially execute arbitrary code with the privileges of the authenticated user. The attack vector is particularly concerning as it operates through standard web interface interactions, making it accessible to attackers with basic knowledge of web application exploitation techniques.
The operational impact of this vulnerability extends beyond simple script execution, as it provides attackers with persistent access to administrative functions within the telephony system. Successful exploitation allows attackers to perform actions such as modifying call logs, accessing sensitive telephony data, creating new user accounts, or even executing arbitrary commands on the underlying system. The vulnerability's presence in the admin/config.php?display=cel URI means that any authenticated user with access to the call event logging feature could be compromised, potentially leading to complete system takeover. This aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter and T1078 for Valid Accounts, as attackers can leverage legitimate administrative access to escalate their privileges and maintain persistence within the network infrastructure. The vulnerability's impact is amplified by the fact that call event logging typically contains sensitive operational data including caller IDs, destination numbers, and call durations that could be exfiltrated or modified.
Mitigation strategies for this vulnerability should prioritize immediate patching of affected versions, with administrators upgrading to the latest available releases that address the XSS injection flaw in the cel module. Organizations should implement input validation and output encoding mechanisms throughout the application to prevent similar vulnerabilities from occurring in other components. The implementation of Content Security Policy headers can provide additional protection against XSS attacks by restricting script execution within the application interface. Network segmentation and least privilege access controls should be enforced to limit the potential damage from successful exploitation, ensuring that even if an attacker gains access to the call event logging functionality, they cannot escalate privileges or access other system components. Regular security auditing and penetration testing should be conducted to identify and remediate similar vulnerabilities in the telephony infrastructure, particularly focusing on input validation mechanisms within administrative interfaces. The vulnerability serves as a reminder of the importance of proper input sanitization and output encoding practices, as outlined in OWASP Top Ten and NIST cybersecurity guidelines, to prevent unauthorized code execution in web applications.