CVE-2023-6506 in WP 2FA Plugin
Summary
by MITRE • 01/11/2024
The WP 2FA – Two-factor authentication for WordPress plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 2.5.0 via the send_backup_codes_email due to missing validation on a user controlled key. This makes it possible for subscriber-level attackers to email arbitrary users on the site.
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Analysis
by VulDB Data Team • 04/11/2026
The WP 2FA – Two-factor authentication for WordPress plugin presents a critical security vulnerability classified as Insecure Direct Object Reference in versions up to and including 2.5.0. This vulnerability specifically affects the send_backup_codes_email functionality, where the plugin fails to properly validate user-controlled input parameters. The flaw allows unauthenticated attackers with subscriber-level privileges to manipulate the system and send backup codes to arbitrary user accounts within the WordPress installation. This represents a significant bypass of the intended authentication security controls that the plugin is designed to enforce.
The technical implementation of this vulnerability stems from insufficient input validation within the plugin's core functionality. When processing the send_backup_codes_email request, the plugin accepts a user-controlled parameter without proper sanitization or authorization checks. This parameter likely contains user identifiers or email addresses that should be validated against legitimate user accounts before processing. The absence of proper access control mechanisms means that any authenticated user, regardless of their role level, can manipulate the parameter to target other users within the system. This type of vulnerability falls under the CWE-639 category, which specifically addresses Insecure Direct Object Reference issues where applications fail to verify that the user is authorized to access the requested resource.
The operational impact of this vulnerability is substantial as it undermines the fundamental security model of two-factor authentication systems. An attacker with subscriber-level access can exploit this flaw to disrupt user authentication processes, potentially leading to account takeovers or social engineering attacks. By sending backup codes to arbitrary users, malicious actors can gain insights into legitimate user accounts and their associated email addresses, creating opportunities for further attacks. This vulnerability particularly affects WordPress environments where multiple user roles exist, as it allows lower-privileged users to perform actions that should be restricted to administrators or users with higher privileges. The attack vector is relatively simple to execute, requiring only basic WordPress authentication and knowledge of the vulnerable plugin version.
Mitigation strategies for this vulnerability should focus on immediate patching of the affected plugin to version 2.5.1 or later, which contains the necessary security fixes. Administrators should also implement additional monitoring of email sending activities within their WordPress installations to detect unusual patterns of backup code distribution. Network-level controls such as rate limiting on email sending functions can help reduce the impact of potential abuse. Organizations should conduct comprehensive security audits of their WordPress plugin ecosystem to identify other potentially vulnerable components. The remediation process should include validating all user inputs and implementing proper authorization checks before processing any object references. This vulnerability highlights the importance of following secure coding practices and proper access control mechanisms, as outlined in the mitre attack framework under the privilege escalation and credential access categories. Regular security assessments and keeping all WordPress components updated remain essential defensive measures against similar Insecure Direct Object Reference vulnerabilities.