CVE-2020-20633 in GDPR Cookie Consent
Summary
by MITRE
ajax_policy_generator in admin/modules/cli-policy-generator/classes/class-policy-generator-ajax.php in GDPR Cookie Consent (cookie-law-info) 1.8.2 and below plugin for WordPress, allows authenticated stored XSS and privilege escalation.
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Analysis
by VulDB Data Team • 08/22/2020
The vulnerability CVE-2020-20633 affects the GDPR Cookie Consent plugin for WordPress, specifically targeting version 1.8.2 and earlier. This issue resides within the ajax_policy_generator function located in the admin/modules/cli-policy-generator/classes/class-policy-generator-ajax.php file. The flaw represents a critical security weakness that enables authenticated attackers to execute stored cross-site scripting attacks while simultaneously escalating their privileges within the WordPress administration interface. The vulnerability stems from insufficient input validation and output escaping mechanisms within the plugin's AJAX handler, which processes user-supplied data without proper sanitization before storing it in the database.
The technical implementation of this vulnerability involves the plugin's administrative AJAX endpoint that generates policy content for cookie consent notices. When authenticated users with sufficient privileges access this endpoint, the system fails to properly sanitize user input before storing it in the WordPress database. This stored data is later rendered in administrative contexts without adequate output encoding, creating conditions for XSS exploitation. The privilege escalation aspect occurs because the vulnerable endpoint operates with elevated permissions, allowing attackers to manipulate administrative functions through malicious input that gets executed in the context of other users with higher privileges.
The operational impact of CVE-2020-20633 extends beyond simple XSS execution as it provides attackers with the capability to gain unauthorized access to administrative functions and potentially compromise entire WordPress installations. An attacker with access to the WordPress admin interface can inject malicious JavaScript code that executes in the context of other administrators or users with higher privileges, potentially leading to full system compromise. The stored nature of the XSS vulnerability means that the malicious payload persists in the database and affects multiple users who view the affected administrative pages. This vulnerability aligns with CWE-79 which describes cross-site scripting flaws, and may map to ATT&CK technique T1059.007 for script execution through web shells or malicious scripts.
Mitigation strategies for this vulnerability require immediate patching of the GDPR Cookie Consent plugin to version 1.8.3 or later, which contains the necessary security fixes. Administrators should also implement additional security measures including regular monitoring of plugin updates, implementing web application firewalls, and conducting thorough security audits of WordPress installations. The vulnerability demonstrates the importance of proper input validation and output encoding in administrative interfaces, particularly when handling user-supplied content that gets stored and later rendered. Organizations should also consider implementing role-based access controls and regular security scanning to identify similar vulnerabilities in other plugins and themes that may present similar attack vectors. Additionally, the incident highlights the necessity of secure coding practices in WordPress plugin development, particularly around AJAX endpoint security and privilege handling mechanisms.