CVE-2019-6264 in Joomla
Summary
by MITRE
An issue was discovered in Joomla! before 3.9.2. Inadequate escaping in mod_banners leads to a stored XSS vulnerability.
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Analysis
by VulDB Data Team • 05/31/2020
The vulnerability identified as CVE-2019-6264 represents a critical stored cross-site scripting flaw within the Joomla websites. The flaw stems from insufficient input validation and output escaping mechanisms that fail to properly sanitize user-supplied data before rendering it in web pages. Attackers can exploit this vulnerability by crafting malicious content through the banner module's administrative interface, which then gets stored in the database and subsequently executed whenever the affected page is accessed by other users. The stored nature of this vulnerability makes it particularly dangerous as it can persist for extended periods and affect multiple users without requiring them to interact with specific malicious links.
The technical implementation of this vulnerability falls under CWE-79 which specifically addresses cross-site scripting flaws in web applications. This weakness occurs when an application incorporates untrusted data into web pages without proper validation or escaping, allowing attackers to inject malicious scripts that execute in the context of other users' browsers. The mod_banners module in Joomla! fails to properly escape HTML characters and special sequences in banner content, particularly in fields such as banner links, alt text, and descriptive content. When these stored values are later rendered in the browser, the unescaped malicious code executes with the privileges of the victim user, potentially leading to session hijacking, credential theft, or further exploitation of the compromised user's privileges.
The operational impact of CVE-2019-6264 extends beyond simple script execution as it enables attackers to establish persistent footholds within Joomla face significant risks including data breaches, service disruption, and potential compliance violations due to inadequate security controls.
Mitigation strategies for CVE-2019-6264 primarily focus on immediate remediation through version upgrading to Joomla installations. According to ATT&CK framework, this vulnerability maps to T1059.001 (Command and Scripting Interpreter: PowerShell) and T1566 (Phishing) as attackers may use the stored XSS to redirect users to phishing sites or execute malicious commands. Regular patch management processes and security awareness training for administrators are essential to prevent exploitation of similar vulnerabilities in the future.