CVE-2017-18540 in WebLibrarian Plugin
Summary
by MITRE
The weblibrarian plugin before 3.4.8.7 for WordPress has XSS via front-end short codes.
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Analysis
by VulDB Data Team • 11/28/2023
The vulnerability identified as CVE-2017-18540 affects the weblibrarian plugin for WordPress, specifically versions prior to 3.4.8.7, and represents a cross-site scripting vulnerability that poses significant security risks to WordPress installations. This issue manifests through front-end shortcodes, which are commonly used to embed dynamic content within WordPress pages and posts. The vulnerability falls under the category of insecure input handling, where user-supplied data is not properly sanitized or validated before being rendered in the browser context.
The technical flaw stems from inadequate output escaping and input validation within the plugin's shortcode implementation. When WordPress processes shortcodes, it typically expects certain parameters to be properly formatted and escaped to prevent malicious code injection. However, the weblibrarian plugin fails to adequately sanitize user-provided input values that are subsequently rendered in the front-end output. This allows attackers to inject malicious javascript code through carefully crafted shortcode parameters, which then executes in the context of other users' browsers when the affected pages are visited.
From an operational impact perspective, this vulnerability creates a persistent threat vector that can be exploited by attackers to perform various malicious activities. The XSS vulnerability enables attackers to steal session cookies, perform unauthorized actions on behalf of users, redirect users to malicious websites, or inject additional malicious content. Given that WordPress is widely used and the plugin affects front-end functionality, the attack surface is substantial and can potentially impact a large number of users. The vulnerability is particularly concerning because it operates at the user-facing interface level, making it difficult to detect and exploit without proper security monitoring.
The weakness aligns with CWE-79, which describes Cross-Site Scripting vulnerabilities where untrusted data is improperly escaped or filtered before being rendered in web pages. This vulnerability also maps to several ATT&CK techniques including T1566 for initial access through malicious web content and T1059 for command and control through injected scripts. The exploitation typically requires minimal technical knowledge and can be automated, making it attractive to threat actors. Organizations using affected versions of the weblibrarian plugin should immediately implement the patch provided in version 3.4.8.7 and conduct thorough security audits of their WordPress installations to identify any potential compromise.
Mitigation strategies should include immediate plugin updates to version 3.4.8.7 or later, along with implementing comprehensive input validation and output escaping mechanisms. Security professionals should also consider implementing content security policies to limit script execution and monitor for unusual shortcode usage patterns. Additionally, regular security scanning of WordPress installations and maintaining updated security baselines can help prevent similar vulnerabilities from being exploited in other plugins or themes. The vulnerability underscores the importance of proper security testing during plugin development and the critical need for maintaining current software versions to protect against known exploits.