CVE-2019-19386 in FusionPBX
Summary
by MITRE
A cross-site scripting (XSS) vulnerability in app/voicemail_greetings/voicemail_greeting_edit.php in FusionPBX 4.4.1 allows remote attackers to inject arbitrary web script or HTML via the id and/or voicemail_id 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 telephony management system where the voicemail greeting edit functionality fails to properly sanitize user input parameters. The flaw specifically affects the app/voicemail_greetings/voicemail_greeting_edit.php script which processes the id and voicemail_id parameters without adequate input validation or output encoding mechanisms. Attackers can exploit this weakness by crafting malicious payloads in these parameters that get executed when the page renders, potentially allowing for session hijacking, credential theft, or redirection to malicious sites. The vulnerability falls under CWE-79 which classifies improper neutralization of input during web page generation as a critical weakness in web applications. This type of vulnerability enables attackers to bypass standard security controls and execute arbitrary code within the context of the victim's browser session, representing a significant risk for organizations relying on FusionPBX for their communication infrastructure. The attack vector is particularly concerning as it requires no authentication to exploit, making it accessible to any remote attacker who can reach the target system.
The operational impact of this vulnerability extends beyond simple script injection as it can be leveraged for more sophisticated attacks within the context of the targeted environment. An attacker could craft malicious payloads that redirect users to phishing sites, steal session cookies, or even inject malicious scripts that persist across user sessions. The vulnerability affects the core voicemail greeting management functionality, which is likely accessed by administrators and users with varying privilege levels, potentially providing attackers with access to sensitive communication data or the ability to manipulate voicemail systems. This weakness aligns with ATT&CK technique T1566 which covers social engineering attacks, particularly those involving malicious web content, and T1059 which encompasses command and scripting interpreters used in executing malicious code. The persistent nature of XSS vulnerabilities means that once exploited, attackers can maintain access to systems for extended periods, making this a particularly dangerous exposure for organizations managing critical communication infrastructure through FusionPBX.
Organizations should implement immediate mitigations including input validation and output encoding for all user-supplied parameters, specifically the id and voicemail_id fields in the affected script. The recommended approach involves implementing strict parameter validation using whitelisting techniques and applying proper HTML encoding to all dynamic content before rendering in web pages. Additionally, organizations should consider implementing Content Security Policy headers to limit the execution of unauthorized scripts and establish proper input sanitization routines that filter out potentially malicious characters and sequences. The fix should include updating to a patched version of FusionPBX where the vulnerability has been addressed through proper parameter validation and input sanitization. Security monitoring should be enhanced to detect suspicious patterns in URL parameters, particularly those containing script tags or unusual character sequences. Organizations should also review their web application security posture and ensure that all input parameters are properly validated and that output encoding is consistently applied across all web interfaces. The vulnerability demonstrates the critical importance of maintaining up-to-date security patches and implementing defense-in-depth strategies that include both perimeter security and application-level protections to prevent successful exploitation of similar weaknesses in other components of the communication infrastructure.