CVE-2019-18834 in Subscriptions Plugin
Summary
by MITRE
Persistent XSS in the WooCommerce Subscriptions plugin before 2.6.3 for WordPress allows remote attackers to execute arbitrary JavaScript because Billing Details are mishandled in WCS_Admin_Post_Types in class-wcs-admin-post-types.php.
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Analysis
by VulDB Data Team • 07/24/2020
The vulnerability CVE-2019-18834 represents a persistent cross-site scripting flaw within the WooCommerce Subscriptions plugin for WordPress, affecting versions prior to 2.6.3. This security issue stems from improper handling of billing details within the WCS_Admin_Post_Types class, specifically in the class-wcs-admin-post-types.php file. The flaw allows remote attackers to inject malicious JavaScript code that persists in the system and executes when unsuspecting users view affected pages. The vulnerability is particularly concerning because it enables attackers to establish persistent malicious presence within the WordPress administration interface, potentially compromising user sessions and gaining unauthorized access to sensitive subscription data.
The technical implementation of this vulnerability involves the mishandling of user input during the processing of billing information within the WooCommerce Subscriptions plugin's administrative interface. When administrators or users view subscription details containing improperly sanitized billing data, the malicious JavaScript code stored in the billing fields executes in the context of the victim's browser. This persistent nature means that the malicious code remains embedded in the database and executes every time the affected page is loaded, making it particularly dangerous for administrators who regularly access subscription management interfaces. The vulnerability directly maps to CWE-79 which describes improper neutralization of input during web page generation, specifically cross-site scripting attacks.
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 potentially steal administrator session cookies, redirect users to malicious sites, modify subscription data, or even escalate privileges within the WordPress system. The persistent nature of the vulnerability means that once an attacker successfully injects malicious code, it continues to affect users until the database is cleaned or the plugin is updated. This makes the vulnerability particularly dangerous in multi-user environments where administrators regularly interact with subscription data and customer billing information.
Mitigation strategies for CVE-2019-18834 require immediate action including updating the WooCommerce Subscriptions plugin to version 2.6.3 or later, which contains the necessary patches to properly sanitize billing details. Organizations should also implement comprehensive input validation and output encoding measures, particularly for administrative interfaces that handle sensitive customer information. Regular security audits of WordPress plugins and themes should be conducted to identify similar vulnerabilities, and administrators should maintain updated security monitoring systems to detect potential exploitation attempts. The vulnerability demonstrates the importance of proper input sanitization in web applications and aligns with ATT&CK technique T1059.007 for Command and Scripting Interpreter: JavaScript, emphasizing the need for robust web application security practices in e-commerce environments where sensitive financial data is processed and stored.