CVE-2015-5528 in Floating Social Bar Plugin
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in the save_order function in class-floating-social-bar.php in the Floating Social Bar plugin before 1.1.6 for WordPress allows remote attackers to inject arbitrary web script or HTML via the items[] parameter in an fsb_save_order action to wp-admin/admin-ajax.php.
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Analysis
by VulDB Data Team • 06/03/2022
The CVE-2015-5528 vulnerability represents a critical cross-site scripting flaw in the Floating Social Bar WordPress plugin, specifically within the save_order function located in class-floating-social-bar.php. This vulnerability affects versions prior to 1.1.6 and exposes WordPress installations to remote code execution risks through malicious script injection. The flaw manifests when the fsb_save_order action is invoked through wp-admin/admin-ajax.php, making it particularly dangerous as it operates through the administrative AJAX endpoint which typically requires authentication but can be exploited through various attack vectors.
The technical implementation of this vulnerability stems from insufficient input validation and output sanitization within the plugin's administrative interface. When the items[] parameter is passed to the save_order function, the plugin fails to properly sanitize user-supplied data before processing it into the database or returning it to the browser. This creates an opening for attackers to inject malicious JavaScript code or HTML content that executes in the context of other users' browsers who visit pages containing the vulnerable plugin functionality. The vulnerability is categorized as CWE-79 - Improper Neutralization of Input During Web Page Generation, which directly maps to the core issue of inadequate sanitization of user-provided data in web applications.
The operational impact of this vulnerability extends beyond simple script injection, as it can enable attackers to perform a range of malicious activities including session hijacking, credential theft, and data exfiltration. An attacker could craft malicious payloads that redirect users to phishing sites, steal administrator credentials, or even modify content on the WordPress site. The attack vector is particularly concerning because it leverages the legitimate administrative AJAX endpoint, making it harder to detect through standard security monitoring. According to ATT&CK framework, this vulnerability maps to T1059.007 - Command and Scripting Interpreter: JavaScript and T1566.001 - Phishing: Spearphishing Attachment, as it enables both code execution and social engineering attacks through the injected scripts.
Mitigation strategies for CVE-2015-5528 require immediate patching of the Floating Social Bar plugin to version 1.1.6 or later, which implements proper input validation and sanitization. Administrators should also implement additional security measures including monitoring of AJAX endpoint access patterns, implementing content security policies to restrict script execution, and conducting regular security audits of installed plugins. The vulnerability highlights the importance of input validation at multiple layers within web applications and demonstrates how seemingly minor flaws in administrative interfaces can create significant security risks. Organizations should also consider implementing web application firewalls and regular vulnerability scanning to detect similar issues in other plugins or custom code implementations.