CVE-2019-19387 in FusionPBX
Summary
by MITRE
A cross-site scripting (XSS) vulnerability in app/fifo_list/fifo_interactive.php in FusionPBX 4.4.1 allows remote attackers to inject arbitrary web script or HTML via the c parameter.
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Analysis
by VulDB Data Team • 03/05/2024
The vulnerability CVE-2019-19387 represents a critical cross-site scripting flaw discovered in FusionPBX version 4.4.1 within the fifo_interactive.php script located in the app/fifo_list directory. This vulnerability manifests as an input validation weakness that fails to properly sanitize user-supplied data before incorporating it into dynamic web content. The specific parameter c serves as the attack vector where malicious input can be injected without adequate filtering or encoding mechanisms, allowing attackers to execute arbitrary web scripts or HTML code within the context of a victim's browser session.
This XSS vulnerability operates under the Common Weakness Enumeration category CWE-79 which specifically addresses "Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')". The flaw enables attackers to manipulate the application's response handling by providing malicious payloads through the c parameter, which then gets rendered in the web interface without proper sanitization. The vulnerability is classified as a remote attack vector since no authentication or local access is required to exploit the flaw, making it particularly dangerous for web applications that are publicly accessible.
The operational impact of this vulnerability extends beyond simple script injection, as it can be leveraged to execute a wide range of malicious activities including session hijacking, credential theft, and redirection to malicious websites. Attackers can craft payloads that exploit the XSS vulnerability to steal cookies, session tokens, or other sensitive information from authenticated users. The vulnerability affects the broader FusionPBX application ecosystem, potentially compromising user data and system integrity. According to ATT&CK framework, this vulnerability maps to T1059.001 (Command and Scripting Interpreter: PowerShell) and T1566.001 (Phishing: Spearphishing Attachment) as attackers can use the XSS payload to redirect users to malicious sites or execute commands within the victim's browser context.
Mitigation strategies for CVE-2019-19387 should focus on implementing proper input validation and output encoding mechanisms. The primary fix involves sanitizing all user-provided input through the c parameter using appropriate encoding functions such as htmlspecialchars() or similar security measures that prevent HTML and script code from being executed. Organizations should also implement Content Security Policy (CSP) headers to add an additional layer of protection against XSS attacks. Additionally, regular security updates and patches should be applied to ensure the application remains protected against known vulnerabilities. The remediation process should include thorough code review of the fifo_interactive.php script and similar components to identify and address other potential input validation weaknesses. Security teams should also consider implementing web application firewalls and monitoring systems to detect and prevent exploitation attempts. Given that this vulnerability affects version 4.4.1 specifically, upgrading to a patched version of FusionPBX represents the most effective long-term solution for addressing the XSS vulnerability and maintaining overall system security posture.