CVE-2018-5311 in Easy Custom Auto Excerpt Plugin
Summary
by MITRE
The Easy Custom Auto Excerpt plugin 2.4.6 for WordPress has XSS via the tonjoo_ecae_options[custom_css] parameter to the wp-admin/admin.php?page=tonjoo_excerpt URI.
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Analysis
by VulDB Data Team • 12/20/2019
The vulnerability identified as CVE-2018-5311 affects the Easy Custom Auto Excerpt plugin version 2.4.6 for WordPress, representing a cross-site scripting flaw that enables unauthorized code execution within user browsers. This vulnerability exists due to insufficient input validation and output sanitization within the plugin's administrative interface, specifically targeting the tonjoo_ecae_options[custom_css] parameter. The affected URI path wp-admin/admin.php?page=tonjoo_excerpt provides an attack vector where malicious actors can inject malicious scripts through the custom_css parameter, potentially compromising the security of WordPress administrators and users who access the plugin's settings page.
The technical implementation of this vulnerability stems from the plugin's failure to properly sanitize user input before rendering it within the web interface. When administrators or users with sufficient privileges navigate to the plugin's configuration page, the unsanitized custom_css parameter values are directly embedded into HTML output without appropriate encoding or filtering mechanisms. This creates an environment where malicious scripts can execute in the context of the victim's browser session, potentially leading to session hijacking, credential theft, or unauthorized administrative actions. The vulnerability is classified as a classic reflected cross-site scripting issue where the malicious payload is delivered through the application's own interface rather than being stored on the server.
The operational impact of this vulnerability extends beyond simple script execution, as it can enable attackers to perform various malicious activities within the compromised WordPress environment. An attacker could exploit this vulnerability to steal administrative credentials, modify plugin settings, inject malicious content into the WordPress dashboard, or redirect users to phishing sites. The risk is particularly elevated for administrators who regularly access the plugin's settings page, as they represent high-value targets for attackers seeking persistent access to the WordPress installation. This vulnerability aligns with CWE-79, which specifically addresses cross-site scripting flaws in web applications, and represents a common attack pattern that has been documented in numerous WordPress plugin vulnerabilities.
Mitigation strategies for CVE-2018-5311 should prioritize immediate plugin updates to versions that address the XSS vulnerability, as the original plugin version 2.4.6 contains the exploitable flaw. Administrators should also implement additional security measures including input validation at the application level, output encoding for all dynamic content, and regular security audits of installed plugins. The vulnerability demonstrates the importance of following secure coding practices such as those outlined in the OWASP Top Ten and ATT&CK framework's web application exploitation techniques, where XSS vulnerabilities represent one of the most frequently exploited weaknesses in content management systems. Organizations should also consider implementing web application firewalls and monitoring for suspicious parameter values in administrative interfaces to detect potential exploitation attempts.