CVE-2015-9537 in NextGEN Gallery
Summary
by MITRE
The NextGEN Gallery plugin before 2.1.10 for WordPress has multiple XSS issues involving thumbnail_width, thumbnail_height, thumbwidth, thumbheight, wmXpos, and wmYpos, and template.
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Analysis
by VulDB Data Team • 02/28/2024
The NextGEN Gallery plugin for WordPress suffered from multiple cross-site scripting vulnerabilities that existed in versions prior to 2.1.10, creating significant security risks for WordPress installations. These vulnerabilities stemmed from insufficient input validation and output sanitization within the plugin's handling of various parameters related to image thumbnail generation and watermark positioning. The affected parameters included thumbnail_width, thumbnail_height, thumbwidth, thumbheight, wmXpos, wmYpos, and template, all of which were susceptible to malicious input injection that could be exploited by unauthorized users to execute arbitrary script code within the context of other users' browsers.
The technical flaw manifested when the plugin failed to properly sanitize user-supplied input values before incorporating them into dynamic HTML output or JavaScript execution contexts. Attackers could manipulate these parameters through various interfaces such as shortcode attributes, URL parameters, or form submissions to inject malicious scripts that would execute whenever affected pages were loaded. The vulnerability was particularly concerning because it allowed attackers to bypass standard security measures and potentially gain unauthorized access to user sessions or execute malicious commands on vulnerable systems. This type of vulnerability falls under CWE-79, which specifically addresses cross-site scripting flaws in web applications, and represents a classic case of improper input validation and output encoding.
The operational impact of these vulnerabilities was substantial as they could be exploited by attackers to perform various malicious activities including session hijacking, defacement of gallery content, or redirection to malicious websites. Users with administrative privileges were particularly at risk since successful exploitation could lead to complete compromise of the WordPress installation. The vulnerabilities were especially dangerous in environments where multiple users interacted with the gallery plugin, as a single malicious input could affect all users viewing the affected pages. This weakness allowed attackers to execute persistent XSS attacks that could remain active until the plugin was updated or the affected parameters were properly sanitized.
Mitigation strategies for these vulnerabilities required immediate patching of the NextGEN Gallery plugin to version 2.1.10 or later, which contained the necessary input validation and sanitization fixes. System administrators should also implement additional security measures such as input validation at the web application firewall level, regular security audits of installed plugins, and monitoring for suspicious parameter usage patterns. The ATT&CK framework categorizes these vulnerabilities under T1059.007 for scripting and T1566.001 for malicious file execution, highlighting the importance of proper input sanitization as a defensive measure. Organizations should also consider implementing Content Security Policy headers to add an additional layer of protection against XSS attacks and regularly update all WordPress plugins to ensure protection against known vulnerabilities.