CVE-2019-19384 in FusionPBX
Summary
by MITRE
A cross-site scripting (XSS) vulnerability in app/fax/fax_log_view.php in FusionPBX 4.4.1 allows remote attackers to inject arbitrary web script or HTML via the fax_uuid parameter.
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Analysis
by VulDB Data Team • 03/05/2024
This cross-site scripting vulnerability exists within the FusionPBX 4.4.1 web application, specifically in the fax_log_view.php script located in the app/fax directory. The flaw represents a classic reflected XSS vulnerability where malicious input is not properly sanitized before being rendered back to users. The vulnerability is triggered when the fax_uuid parameter is passed through the URL and subsequently processed without adequate input validation or output encoding, creating an attack vector that can be exploited by remote adversaries.
The technical implementation of this vulnerability stems from insufficient sanitization of user-supplied input within the fax_uuid parameter. When a user visits a crafted URL containing malicious script in the fax_uuid value, the application fails to properly escape or encode this input before displaying it in the web page context. This allows attackers to inject malicious JavaScript code or HTML content that executes in the victim's browser when they access the affected page. The vulnerability falls under CWE-79 which specifically addresses Cross-Site Scripting flaws in web applications, representing a critical security weakness that enables unauthorized code execution in user browsers.
The operational impact of this vulnerability is significant as it can be exploited to perform various malicious activities including session hijacking, credential theft, data exfiltration, and redirection to malicious websites. Attackers can craft phishing pages that appear legitimate to users, potentially leading to unauthorized access to the FusionPBX system. The vulnerability affects any user who visits a maliciously crafted URL containing the XSS payload, making it particularly dangerous in environments where multiple users access the same system. The reflected nature of this XSS means that the malicious script is executed immediately when the victim clicks on the crafted link, without requiring persistent storage or complex attack chains.
Organizations using FusionPBX 4.4.1 should implement immediate mitigations including input validation and output encoding for all user-supplied parameters. The recommended approach involves implementing proper HTML escaping for all dynamic content rendered in web pages, particularly for parameters like fax_uuid that are directly used in output generation. Input validation should be implemented at multiple layers including application-level sanitization and parameter validation. Additionally, implementing Content Security Policy headers can provide additional defense-in-depth against XSS attacks by restricting script execution. The vulnerability aligns with ATT&CK technique T1566.001 which covers phishing with malicious attachments and links, making it a critical concern for organizations that may be targeted through social engineering campaigns. System administrators should also consider upgrading to patched versions of FusionPBX as soon as possible, as this vulnerability represents a known security flaw that has been addressed in subsequent releases.