CVE-2017-7986 in Joomla
Summary
by MITRE
In Joomla! 1.5.0 through 3.6.5 (fixed in 3.7.0), inadequate filtering of specific HTML attributes leads to XSS vulnerabilities in various components.
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Analysis
by VulDB Data Team • 12/21/2020
The vulnerability identified as CVE-2017-7986 represents a critical cross-site scripting flaw affecting Joomla framework, making it particularly dangerous as it can be exploited across various attack vectors within the platform's architecture. The flaw specifically targets the sanitization of HTML attributes, allowing attackers to bypass security controls that should prevent potentially harmful markup from being rendered in user-facing interfaces.
From a technical perspective, the vulnerability manifests when the application fails to properly filter or escape specific HTML attributes that could contain malicious payloads. This inadequate filtering allows attackers to inject attributes such as onclick, onmouseover, or other event handlers that can execute JavaScript code when users interact with the compromised content. The issue is classified under CWE-79, which specifically addresses Cross-Site Scripting vulnerabilities in software applications. The vulnerability's exploitation requires minimal privileges and can be executed through standard user input fields, forms, or even administrative interfaces where content is rendered. The security implications extend beyond simple script execution as these XSS vectors can be leveraged to steal session cookies, redirect users to malicious sites, or perform actions on behalf of authenticated users.
The operational impact of CVE-2017-7986 is substantial given Joomla!'s widespread adoption across web applications, particularly in enterprise environments where content management systems handle sensitive data and user interactions. Attackers can exploit this vulnerability to perform session hijacking attacks, steal administrator credentials, or manipulate content displayed to end users. The vulnerability's presence in versions through 3.6.5 means that organizations running these older versions face significant risk, as the flaw can be exploited through various attack surfaces including user registration forms, comment sections, article submissions, and administrative interfaces. From an ATT&CK framework perspective, this vulnerability maps to T1059.007 for Command and Scripting Interpreter: JavaScript and T1566 for Phishing with Malicious Attachments, as it enables attackers to deliver malicious JavaScript payloads through compromised web forms. The vulnerability also aligns with T1190 for Exploit Public-Facing Application, as it represents a common attack vector through which external threat actors can gain access to systems.
Organizations affected by this vulnerability should immediately implement the patch released in Joomla! version 3.7.0, which addresses the HTML attribute filtering mechanism and enhances input validation throughout the application. Additional mitigations include implementing Content Security Policy headers to limit script execution, deploying web application firewalls to detect and block malicious payloads, and conducting thorough security audits of all user-input handling components. Security teams should also consider implementing input sanitization at multiple layers, including application-level validation, database-level filtering, and network-level monitoring to detect potential exploitation attempts. The vulnerability serves as a reminder of the critical importance of proper input validation and output encoding in preventing XSS attacks, particularly in content management systems where user-generated content is prevalent and security controls must be robust enough to handle various attack scenarios.