CVE-2017-17869 in mgl-instagram-gallery Plugin
Summary
by MITRE
The mgl-instagram-gallery plugin for WordPress has XSS via the single-gallery.php media parameter.
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Analysis
by VulDB Data Team • 12/18/2019
The vulnerability identified as CVE-2017-17869 represents a cross-site scripting flaw within the mgl-instagram-gallery WordPress plugin, specifically affecting the single-gallery.php script. This issue arises from inadequate input validation and sanitization of the media parameter, which allows malicious actors to inject arbitrary JavaScript code into the plugin's output. The vulnerability exists because the plugin fails to properly escape or filter user-supplied data before rendering it in the web page context, creating an exploitable vector for attackers to execute malicious scripts in the browsers of unsuspecting users.
The technical nature 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 occurs when the media parameter from the single-gallery.php script is directly used in HTML output without appropriate sanitization measures. Attackers can craft malicious URLs containing JavaScript payloads within the media parameter, which then get executed when other users view the gallery page. This type of vulnerability falls under the ATT&CK technique T1531 for Application Layer Protocol: Web Protocols and can be leveraged for session hijacking, credential theft, or redirection to malicious sites.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform various malicious activities within the context of the affected WordPress site. An attacker could inject scripts that steal user session cookies, redirect visitors to phishing sites, or even modify the gallery content to display malicious advertisements. The vulnerability affects all versions of the mgl-instagram-gallery plugin that fail to properly sanitize the media parameter, potentially compromising any WordPress installation using this plugin. The attack vector is relatively straightforward, requiring only that users navigate to a specially crafted URL containing the malicious payload, making it particularly dangerous in environments where users may inadvertently click on compromised links.
Mitigation strategies for this vulnerability should include immediate patching of the mgl-instagram-gallery plugin to version 1.0.8 or later, which contains the necessary input validation fixes. System administrators should also implement proper input sanitization measures such as HTML escaping and output encoding for all user-supplied data within the plugin's code. Additionally, implementing content security policies can provide an additional layer of protection by restricting the sources from which scripts can be loaded. Regular security audits and monitoring of plugin updates are essential for maintaining WordPress site security, as this vulnerability demonstrates the critical importance of proper input validation in web applications. The remediation process should also include reviewing other plugins for similar vulnerabilities and ensuring that all WordPress core, theme, and plugin components remain current with security patches.