CVE-2019-9919 in Harmis JE Messenger
Summary
by MITRE
An issue was discovered in the Harmis JE Messenger component 1.2.2 for Joomla!. It is possible to craft messages in a way that JavaScript gets executed on the side of the receiving user when the message is opened, aka XSS.
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Analysis
by VulDB Data Team • 08/17/2023
The CVE-2019-9919 vulnerability represents a critical cross-site scripting flaw within the Harmis JE Messenger component version 1.2.2 for Joomla! platforms. This security weakness allows attackers to inject malicious JavaScript code into message content that executes automatically when recipients open the compromised messages. The vulnerability specifically affects web applications built on the Joomla content management system where the Harmis JE Messenger component is installed, creating a persistent threat vector for unauthorized code execution in user browsers.
The technical implementation of this XSS vulnerability stems from insufficient input validation and output encoding within the message handling functionality of the Harmis JE Messenger component. When users compose messages containing malicious script payloads, the component fails to properly sanitize or escape these inputs before rendering them in the recipient's browser environment. This processing gap enables attackers to embed JavaScript code within message content that gets executed in the context of the victim's browser session, potentially compromising user data and system integrity.
The operational impact of CVE-2019-9919 extends beyond simple script execution, as it creates opportunities for more sophisticated attacks including session hijacking, credential theft, and data exfiltration. Attackers can leverage this vulnerability to establish persistent access to user accounts, manipulate message content, or redirect users to malicious domains. The vulnerability particularly affects Joomla! installations where users frequently exchange messages through the Harmis JE Messenger component, making it a significant threat to organizations relying on this messaging functionality for communication purposes. This weakness aligns with CWE-79, which categorizes cross-site scripting vulnerabilities as a primary concern for web application security.
Mitigation strategies for CVE-2019-9919 should prioritize immediate component updates to versions that address the XSS vulnerability, as provided by the vendor. Organizations should implement comprehensive input validation and output encoding mechanisms to prevent malicious script injection, while also considering web application firewalls and content security policies as additional protective layers. Security teams must conduct thorough vulnerability assessments of all Joomla! installations to identify potential exposure points, and implement proper user access controls to limit message creation privileges. The remediation process should include regular security audits and monitoring of message handling components, following ATT&CK framework techniques for defensive measures against client-side exploitation vectors. Regular patch management procedures should be established to ensure timely deployment of security updates and prevent similar vulnerabilities from being exploited in the future.