CVE-2017-7987 in Joomla
Summary
by MITRE
In Joomla! 3.2.0 through 3.6.5 (fixed in 3.7.0), inadequate escaping of file and folder names leads to XSS vulnerabilities in the template manager component.
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Analysis
by VulDB Data Team • 05/31/2020
The vulnerability identified as CVE-2017-7987 affects Joomla! content management systems versions 3.2.0 through 3.6.5, representing a critical cross-site scripting weakness within the template manager component. This flaw stems from insufficient input validation and output escaping mechanisms that fail to properly sanitize user-supplied data when processing file and folder names. The vulnerability exists in the administrative interface where users can manage templates and their associated files, creating an attack surface that could be exploited by malicious actors to inject malicious scripts into the web application's response. The issue specifically manifests when the system displays file and folder names without adequate HTML escaping, allowing attackers to craft malicious inputs that persist in the user interface and execute in the context of other users' browsers.
The technical implementation of this vulnerability aligns with CWE-79, which describes cross-site scripting flaws where untrusted data is incorporated into web pages without proper validation or escaping. The flaw operates through the template manager's file listing functionality where folder and file names are directly rendered in HTML output without appropriate sanitization. Attackers can exploit this by uploading or renaming files with malicious script content in their names, which then get displayed in the template manager interface. When other administrators or users view these listings, the malicious scripts execute in their browser context, potentially leading to session hijacking, privilege escalation, or data exfiltration. The vulnerability demonstrates a classic improper output escaping pattern where the application fails to neutralize special characters that could alter the intended execution context of HTML content.
The operational impact of CVE-2017-7987 extends beyond simple script execution as it provides attackers with potential access to administrative functions and sensitive data within the Joomla! environment. An attacker who successfully exploits this vulnerability can manipulate the template manager interface to execute arbitrary JavaScript code in the browser of any user who views the affected file listings. This capability enables sophisticated attacks including session cookie theft, redirection to malicious sites, and potentially full system compromise if the attacker can leverage the privileges of the affected user. The vulnerability's exploitation is particularly concerning in multi-user environments where administrators frequently access the template manager, as it could allow attackers to establish persistent access to the administrative interface. Additionally, the vulnerability may facilitate privilege escalation attacks if the attacker can manipulate file operations to gain elevated system access.
Mitigation strategies for CVE-2017-7987 require immediate implementation of the official Joomla platform, as this vulnerability may indicate broader input validation weaknesses that require additional attention.