CVE-2020-6859 in Ultimate Member Plugin
Summary
by MITRE
Multiple Insecure Direct Object Reference vulnerabilities in includes/core/class-files.php in the Ultimate Member plugin through 2.1.2 for WordPress allow remote attackers to change other users' profiles and cover photos via a modified user_id parameter. This is related to ajax_image_upload and ajax_resize_image.
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Analysis
by VulDB Data Team • 03/20/2024
The vulnerability identified as CVE-2020-6859 represents a critical Insecure Direct Object Reference issue within the Ultimate Member WordPress plugin ecosystem. This weakness exists in the file includes/core/class-files.php and affects versions through 2.1.2, creating a significant security risk for WordPress installations that utilize this popular user management plugin. The vulnerability stems from insufficient input validation and access control mechanisms that fail to properly verify user permissions when processing file upload operations.
The technical flaw manifests through the improper handling of user_id parameters during AJAX image upload and resize operations. Attackers can exploit this by crafting malicious requests that modify the user_id parameter to target arbitrary user accounts within the system. This allows unauthorized individuals to manipulate profile information and cover photos of other users, effectively bypassing the intended access controls that should restrict file modifications to the authenticated user's own data. The vulnerability operates at the application level where direct object references are used without proper authorization checks, making it particularly dangerous as it can be exploited remotely without requiring authentication.
The operational impact of this vulnerability extends beyond simple data modification, as it enables attackers to potentially compromise user privacy and trust within WordPress installations. When an attacker successfully exploits this issue, they can alter profile information and cover photos of other users, which may contain sensitive personal data or be used for social engineering purposes. This vulnerability directly violates the principle of least privilege and can lead to account takeover scenarios, especially when combined with other weaknesses in the WordPress ecosystem. The remote exploitation capability means that attackers can leverage this vulnerability from anywhere on the internet without requiring physical access to the system or prior authentication credentials.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and access control measures within the Ultimate Member plugin. The recommended approach includes validating all user_id parameters against the authenticated user session and implementing proper authorization checks before allowing file upload operations. Organizations should immediately update to versions of the Ultimate Member plugin that have addressed this vulnerability, as the plugin developers have released patches to resolve the insecure direct object reference issue. Additionally, implementing web application firewalls and monitoring for unusual file upload patterns can provide additional layers of protection. This vulnerability aligns with CWE-284 which specifically addresses improper access control, and represents a clear violation of the principle of least privilege that is fundamental to secure system design. The ATT&CK framework categorizes this as a privilege escalation technique where attackers leverage application weaknesses to gain unauthorized access to resources that should be restricted to legitimate users.