CVE-2019-11409 in FreePBX
Summary
by MITRE
app/operator_panel/exec.php in the Operator Panel module in FreePBX 4.4.3 suffers from a command injection vulnerability due to a lack of input validation that allows authenticated non-administrative attackers to execute commands on the host. This can further lead to remote code execution when combined with an XSS vulnerability also present in the FusionPBX Operator Panel module.
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Analysis
by VulDB Data Team • 05/26/2025
The vulnerability identified as CVE-2019-11409 resides within the Operator Panel module of FreePBX version 4.4.3 specifically in the exec.php file. This represents a critical command injection flaw that arises from insufficient input validation mechanisms within the application's codebase. The vulnerability affects the Operator Panel module which is designed to provide administrative functions for telephone systems but fails to properly sanitize user inputs before processing them. The flaw allows authenticated users who lack administrative privileges to exploit this weakness and execute arbitrary commands on the underlying host system.
The technical nature of this vulnerability aligns with CWE-77 and CWE-88 categories, which specifically address command injection flaws where attacker-controlled data is passed to system execution functions without proper sanitization. The vulnerability occurs because the application directly incorporates user-supplied parameters into system command calls without adequate validation or escaping mechanisms. This creates a pathway for malicious input to be interpreted as shell commands rather than benign data, enabling attackers to execute arbitrary code with the privileges of the web application user.
The operational impact of this vulnerability extends beyond simple command execution to potentially enable full system compromise when combined with other vulnerabilities present in the FusionPBX ecosystem. The fact that this vulnerability can be exploited by non-administrative users means that even limited access to the system can be escalated to full system control. When combined with an existing XSS vulnerability in the same FusionPBX Operator Panel module, attackers can chain these exploits to achieve remote code execution without requiring additional authentication. This combination creates a particularly dangerous scenario where a single user with basic access can potentially gain complete control over the telephony infrastructure.
The security implications of this vulnerability are severe given that FreePBX is widely deployed in enterprise and organizational environments for voice communication systems. The attack surface is expanded because the vulnerability requires only authenticated access, which is often easier to obtain than administrative credentials. Attackers could potentially use this vulnerability to install backdoors, exfiltrate sensitive telephony data, or disrupt critical communication services. The impact extends to compliance and regulatory concerns as organizations may be required to maintain audit trails and ensure proper segregation of duties in their communication systems. Organizations should implement immediate mitigations including patching to the latest FreePBX versions, network segmentation to limit access to the Operator Panel module, and monitoring for suspicious command execution patterns. Additionally, implementing proper input validation and output encoding mechanisms would prevent similar vulnerabilities from occurring in the future. The vulnerability demonstrates the critical importance of validating all user inputs and following secure coding practices to prevent command injection attacks that can lead to complete system compromise.