CVE-2018-17138 in Jibu Pro Plugin
Summary
by MITRE
The Jibu Pro plugin through 1.7 for WordPress is prone to Stored XSS via the wp-content/plugins/jibu-pro/quiz_action.php name (aka Quiz Name) field.
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Analysis
by VulDB Data Team • 03/24/2020
The CVE-2018-17138 vulnerability affects the Jibu Pro plugin version 1.7 and earlier for WordPress, representing a critical stored cross-site scripting flaw that allows attackers to inject malicious code into the plugin's quiz creation functionality. This vulnerability specifically targets the Quiz Name field within the wp-content/plugins/jibu-pro/quiz_action.php endpoint, where user input is not properly sanitized or validated before being stored in the database and subsequently rendered in subsequent page requests. The flaw enables attackers to execute arbitrary JavaScript code within the context of other users' browsers who view the affected quiz data, making it particularly dangerous in multi-user environments where administrators and regular users may interact with the same content.
The technical implementation of this vulnerability stems from insufficient input validation and output escaping mechanisms within the plugin's backend processing. When administrators or users create quizzes through the web interface, the Quiz Name parameter is directly processed without proper sanitization of potentially malicious input. The stored data is then retrieved and displayed in various contexts throughout the plugin's user interface, creating multiple opportunities for XSS execution. This type of vulnerability falls under CWE-79 which specifically addresses Cross-Site Scripting flaws, and more precisely maps to CWE-80 which details the storage of untrusted data without proper validation. The vulnerability's impact is amplified because it affects the plugin's core functionality and can be exploited by both authenticated and unauthenticated attackers depending on the plugin's configuration and user permissions.
The operational impact of CVE-2018-17138 extends beyond simple script execution, as it can enable attackers to perform a wide range of malicious activities including session hijacking, data exfiltration, and privilege escalation within the WordPress environment. An attacker who successfully exploits this vulnerability could steal administrator credentials, modify quiz content to redirect users to malicious sites, or inject persistent backdoors into the WordPress installation. The stored nature of this XSS vulnerability means that the malicious payload remains active even after the initial exploit, continuously affecting any user who views the compromised quiz data. This makes the vulnerability particularly attractive to attackers seeking long-term access to WordPress sites, as it provides a persistent foothold that can survive system restarts and routine maintenance activities. The vulnerability also aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter: JavaScript, and T1566.001 for Phishing: Spearphishing Attachment, as it enables both client-side exploitation and social engineering attacks that leverage the compromised quiz functionality.
Mitigation strategies for CVE-2018-17138 should prioritize immediate plugin updates to version 1.8 or later where the vulnerability has been patched, as the vendor has addressed the input sanitization issues in subsequent releases. Organizations should implement comprehensive input validation and output encoding measures at multiple layers, including web application firewall rules that filter suspicious patterns in quiz name fields, and regular security scanning of WordPress installations to identify similar vulnerabilities. The patch addresses the core issue by implementing proper sanitization of user inputs and ensuring that all stored data is properly escaped before rendering in HTML contexts. Security teams should also conduct thorough penetration testing of WordPress plugins to identify similar storage-related XSS vulnerabilities and implement defense-in-depth strategies including content security policies that limit script execution capabilities and regular monitoring of plugin directories for unauthorized modifications. Additionally, administrators should enforce least privilege access controls and monitor user activities related to quiz creation and modification to detect potential exploitation attempts.