CVE-2023-2439 in UserPro Plugin
Summary
by MITRE • 01/31/2024
The UserPro plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the 'userpro' shortcode in versions up to, and including, 5.1.5 due to insufficient input sanitization and output escaping on user supplied attributes. This makes it possible for authenticated attackers with contributor-level and above permissions to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page.
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Analysis
by VulDB Data Team • 02/22/2024
The CVE-2023-2439 vulnerability affects the UserPro plugin for WordPress, specifically targeting versions up to and including 5.1.5. This represents a critical security flaw that enables stored cross-site scripting attacks through the 'userpro' shortcode functionality. The vulnerability stems from inadequate input sanitization and output escaping mechanisms within the plugin's codebase, creating a persistent security risk that can be exploited by authenticated attackers who possess contributor-level permissions or higher. The issue is particularly concerning because it allows attackers to inject malicious scripts that execute whenever any user accesses a page containing the injected content, making it a significant threat to WordPress site integrity and user safety.
The technical implementation of this vulnerability occurs through the userpro shortcode which processes user-supplied attributes without proper sanitization before rendering them in web pages. When an attacker with sufficient privileges creates or modifies content using this shortcode, they can inject malicious JavaScript code that gets stored within the WordPress database. This stored script then executes in the context of other users' browsers when they access pages containing the compromised shortcode, creating a persistent vector for attack. The vulnerability directly maps to CWE-79 - Improper Neutralization of Input During Web Page Generation, which is a fundamental weakness in web application security where user input is not properly escaped before being rendered in web pages. The flaw demonstrates poor input validation and output escaping practices that violate basic web security principles.
The operational impact of CVE-2023-2439 extends beyond simple script injection, as it provides attackers with a persistent foothold within WordPress installations. Once exploited, the malicious scripts can perform various harmful activities including cookie theft, session hijacking, redirection to malicious sites, and data exfiltration. The vulnerability affects all users who access pages containing the compromised shortcode, making it particularly dangerous in multi-user environments where contributors and higher-level users have elevated privileges. Attackers can leverage this weakness to establish long-term access to WordPress sites, potentially leading to complete compromise of the installation. The attack vector is particularly insidious because it requires minimal privileges and can remain undetected for extended periods, aligning with ATT&CK technique T1566.001 - Phishing: Spearphishing Attachment for initial compromise and T1059.001 - Command and Scripting Interpreter: PowerShell for potential post-exploitation activities.
Organizations affected by this vulnerability should immediately implement multiple layers of defense to mitigate the risk. The primary recommendation involves updating to the latest version of the UserPro plugin where the vulnerability has been patched, though administrators should verify the patch addresses the specific input sanitization and output escaping issues. Additionally, implementing strict input validation and output escaping measures within the WordPress environment can provide defense-in-depth protection. Security monitoring should be enhanced to detect anomalous shortcode usage patterns, and user privilege management should be reviewed to ensure that only necessary users have contributor-level access or higher. Network-based intrusion detection systems can help identify potential exploitation attempts, while regular security audits of WordPress plugins should be conducted to identify similar vulnerabilities. The remediation process should also include thorough testing of the patched plugin to ensure no regression issues are introduced while maintaining the plugin's core functionality and user experience.