CVE-2019-16982 in FusionPBX
Summary
by MITRE
In FusionPBX up to v4.5.7, the file app\access_controls\access_control_nodes.php uses an unsanitized "id" variable coming from the URL, which is reflected in HTML, leading to XSS.
Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.
Analysis
by VulDB Data Team • 01/17/2024
The vulnerability identified as CVE-2019-16982 affects FusionPBX versions up to v4.5.7 and represents a classic cross-site scripting flaw that resides within the access control nodes management functionality. This issue stems from improper input validation and sanitization practices within the application's codebase, specifically in the file app_access_controls_access_control_nodes.php which processes user-supplied identifiers from web requests.
The technical flaw manifests when the application accepts an "id" parameter directly from URL query strings without adequate sanitization or validation. This unsanitized variable gets incorporated into HTML output without proper encoding or escaping mechanisms, creating an exploitable condition where malicious actors can inject arbitrary JavaScript code into the web application's response. The vulnerability follows the CWE-79 pattern of cross-site scripting, where untrusted data flows from the web server to the user's browser without proper sanitization.
The operational impact of this vulnerability is significant as it allows remote attackers to execute malicious scripts in the context of authenticated users' browsers. An attacker could craft malicious URLs containing crafted JavaScript payloads that would execute whenever a victim accesses the vulnerable page. This could lead to session hijacking, credential theft, data exfiltration, or the execution of unauthorized administrative actions within the FusionPBX application. The attack requires no special privileges beyond access to the vulnerable web interface, making it particularly dangerous in environments where FusionPBX is exposed to untrusted networks.
Mitigation strategies for CVE-2019-16982 should focus on immediate code-level fixes including input sanitization and output encoding practices. The application should implement proper parameter validation to ensure that the "id" variable contains only expected data types and formats before processing. Additionally, all user-supplied data should be properly escaped or encoded before being rendered in HTML contexts, following the OWASP XSS prevention guidelines. The most effective long-term solution involves upgrading to FusionPBX version 4.5.8 or later, which contains the necessary patches to address this vulnerability. Organizations should also implement web application firewalls and input validation rules to detect and block malicious payloads targeting similar vulnerabilities. The ATT&CK framework categorizes this vulnerability under T1213 (Data from Information Repositories) and T1566 (Phishing) as attackers could leverage the XSS to harvest credentials or redirect users to malicious sites, while the CWE-79 classification emphasizes the need for robust input validation and output encoding mechanisms to prevent such client-side code injection attacks.