CVE-2018-0589 in Ultimate Member Plugin
Summary
by MITRE
Ultimate Member plugin prior to version 2.0.4 for WordPress allows remote authenticated attackers to bypass access restriction to add a new form in the 'Forms' page via unspecified vectors.
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Analysis
by VulDB Data Team • 02/05/2020
The CVE-2018-0589 vulnerability affects the Ultimate Member WordPress plugin, a popular user management and membership solution that enables site administrators to create custom user registration forms, profiles, and access controls. This particular flaw exists in versions prior to 2.0.4 and represents a critical access control bypass issue that undermines the plugin's core security mechanisms. The vulnerability specifically targets the administrative interface of the plugin, particularly the 'Forms' page functionality, where authorized users should be restricted from performing certain operations. The issue stems from inadequate permission validation within the plugin's codebase, allowing authenticated attackers to exploit unspecified vectors that should normally be protected by proper access controls. This flaw essentially permits malicious users with lower privileges to execute actions that should only be available to administrators or users with elevated permissions, creating a significant security risk for WordPress installations that rely on this plugin for user management.
The technical implementation of this vulnerability demonstrates a classic privilege escalation weakness within the plugin's administrative routing system. Attackers who have authenticated access to the WordPress site with any user account can exploit this flaw to bypass the normal access restrictions that govern form creation within the Ultimate Member plugin. The unspecified vectors mentioned in the CVE description suggest that the vulnerability may stem from improper capability checks, missing nonce validations, or flawed user role verification mechanisms that should have prevented unauthorized access to administrative functions. This type of vulnerability typically falls under CWE-285, which addresses improper authorization issues in software systems, and represents a clear violation of the principle of least privilege that security frameworks mandate for all administrative interfaces. The vulnerability's impact extends beyond simple privilege escalation as it allows attackers to potentially create malicious forms that could be used for data exfiltration, user manipulation, or further exploitation of the WordPress environment.
The operational impact of CVE-2018-0589 is substantial for WordPress administrators who rely on Ultimate Member for user management and access control. An attacker who successfully exploits this vulnerability can add new forms to the system, potentially creating forms that capture user credentials, personal information, or other sensitive data. This capability enables attackers to establish persistent access points within the WordPress environment and could lead to complete compromise of user accounts and data. The vulnerability is particularly dangerous because it requires only authenticated access, meaning that even users with basic contributor or subscriber roles could potentially exploit this issue. The attack vector represents a significant concern for organizations that use Ultimate Member for membership management, as it could allow unauthorized individuals to manipulate the user registration and profile systems. This vulnerability also aligns with ATT&CK technique T1078 which covers valid accounts as a means of gaining access, and T1548 which addresses privilege escalation through access control bypass mechanisms.
Mitigation strategies for CVE-2018-0589 require immediate action from WordPress administrators who use the Ultimate Member plugin. The most effective solution is to upgrade to version 2.0.4 or later, which includes proper access control checks and validation mechanisms that prevent unauthorized form creation. Organizations should implement comprehensive patch management procedures to ensure all WordPress plugins are kept up to date with the latest security fixes. Additionally, administrators should conduct thorough security audits of their WordPress installations to identify other potential vulnerabilities in the plugin ecosystem. Network monitoring solutions should be configured to detect unusual administrative activities, particularly unauthorized form creation attempts that could indicate exploitation of this vulnerability. The incident highlights the importance of implementing proper security controls such as two-factor authentication, role-based access controls, and regular security assessments. Organizations should also consider implementing web application firewalls to detect and block malicious requests targeting known vulnerability patterns. Security teams should review their incident response procedures to ensure they can quickly detect and respond to exploitation attempts targeting access control bypass vulnerabilities in WordPress plugins, as these issues often serve as initial entry points for more sophisticated attacks.