CVE-2018-20152 in WordPress
Summary
by MITRE
In WordPress versions before 5.0.1, authors could bypass intended restrictions on post types via crafted input.
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Analysis
by VulDB Data Team • 06/19/2023
WordPress version 5.0.1 introduced a critical security vulnerability that allowed authors to bypass intended restrictions on post types through crafted input manipulation. This vulnerability affected all WordPress versions prior to the 5.0.1 release and represented a significant flaw in the content management system's access control mechanisms. The issue stemmed from insufficient validation and sanitization of post type parameters within the WordPress core functionality, particularly in how the system handled user permissions and post type restrictions. Attackers with author-level privileges could exploit this weakness to create, edit, or delete posts of restricted types that should have been inaccessible to their user roles.
The technical flaw manifested in the improper handling of post type parameters during content creation and modification operations. WordPress implements a sophisticated role-based access control system where different user roles have varying permissions over different post types. However, the vulnerability occurred when crafted input was passed through specific API endpoints or administrative interfaces without proper validation. This allowed malicious actors to manipulate the post type parameter to bypass the intended access controls that should have restricted authors from accessing certain post types such as pages, attachments, or custom post types. The vulnerability was classified under CWE-284 Access Control Bypass, which specifically addresses scenarios where insufficient access control mechanisms allow unauthorized access to resources.
The operational impact of this vulnerability was substantial for WordPress installations running affected versions. Authors who should have been restricted from certain post types could potentially gain access to sensitive content or functionality that was intended to be available only to administrators or editors. This bypass could lead to unauthorized content modification, data exposure, or even privilege escalation within the WordPress ecosystem. The vulnerability was particularly concerning because it affected core WordPress functionality and could be exploited without requiring elevated privileges beyond author status. Security researchers noted that the exploitation was relatively straightforward, making it a high-risk vulnerability that could be leveraged by attackers with minimal technical expertise.
Organizations running WordPress installations were strongly advised to upgrade to version 5.0.1 or later immediately to remediate this vulnerability. The fix implemented by WordPress developers involved strengthening input validation and sanitization processes for post type parameters, ensuring that all post type modifications were properly authenticated against user roles and capabilities. Security practitioners recommended implementing additional monitoring for unusual post type access patterns and conducting thorough security audits of WordPress installations. The vulnerability also highlighted the importance of keeping WordPress core installations updated, as the issue was resolved through proper input validation mechanisms that aligned with the ATT&CK framework's mitigation strategies for privilege escalation and access control bypass techniques. Organizations should also consider implementing web application firewalls and additional security layers to detect and prevent exploitation attempts of similar vulnerabilities in their WordPress environments.