CVE-2025-34077: WordPress Pie Register Auth Bypass Flaw

CVE-2025-34077 Overview

CVE-2025-34077 is a critical authentication bypass vulnerability affecting the WordPress Pie Register plugin version 3.7.1.4 and earlier. This flaw enables unauthenticated attackers to impersonate arbitrary users, including administrators, by exploiting improper validation in the plugin's social login functionality. The vulnerability allows attackers to craft malicious POST requests that bypass authentication controls, potentially leading to complete site compromise through subsequent remote code execution.

Critical Impact

Unauthenticated attackers can gain administrative access to WordPress installations and achieve remote code execution by uploading malicious plugins containing arbitrary PHP code.

Affected Products

• WordPress Pie Register Plugin ≤ 3.7.1.4
• WordPress installations using vulnerable Pie Register versions
• Web servers hosting affected WordPress sites

Discovery Timeline

• 2025-07-09 - CVE-2025-34077 published to NVD
• 2025-07-10 - Last updated in NVD database

Technical Details for CVE-2025-34077

Vulnerability Analysis

The vulnerability resides in the Pie Register plugin's handling of social authentication requests. The plugin fails to properly validate the authenticity of social login attempts, allowing attackers to forge authentication requests that bypass normal credential verification. When a POST request is submitted to the login endpoint with social_site=true and a manipulated user_id_social_site parameter, the plugin incorrectly trusts these client-supplied values and generates a valid WordPress session cookie for the specified user ID.

This authentication bypass is classified under CWE-94 (Improper Control of Generation of Code), as the subsequent exploitation chain allows for arbitrary code execution. The attack requires no prior authentication and can be executed remotely over the network without user interaction, making it particularly dangerous for internet-facing WordPress installations.

Root Cause

The root cause of this vulnerability is insufficient validation of user-supplied parameters during the social authentication flow. The Pie Register plugin trusts the social_site and user_id_social_site parameters without verifying that the authentication request originated from a legitimate social login provider. This design flaw allows attackers to arbitrarily specify any user ID, effectively bypassing all authentication controls.

Attack Vector

The attack is network-based and can be executed by any unauthenticated remote attacker. The exploitation process follows a two-stage approach:

1. Authentication Bypass: The attacker sends a crafted POST request to the WordPress login endpoint with the social_site parameter set to true and the user_id_social_site parameter set to the target user's ID (typically 1 for administrator accounts). The plugin processes this request as a legitimate social login and generates a valid session cookie.

2. Remote Code Execution: Once authenticated as an administrator, the attacker leverages WordPress's plugin upload functionality to install a malicious plugin containing arbitrary PHP code. This payload executes on the underlying web server, granting the attacker complete control over the system.

The existence of a Metasploit Exploit Module and Exploit-DB entry demonstrates that weaponized exploits are publicly available, significantly increasing the risk of exploitation in the wild.

Detection Methods for CVE-2025-34077

Indicators of Compromise

• Unexpected POST requests to WordPress login endpoints containing social_site=true parameter
• Authentication events for administrator accounts without corresponding legitimate login activity
• New or modified plugins appearing in the WordPress installation without authorized changes
• Suspicious PHP files in plugin directories, particularly those with obfuscated or encoded content
• Web server logs showing requests from unusual IP addresses accessing admin functionality

Detection Strategies

• Monitor web application firewall (WAF) logs for POST requests containing social_site and user_id_social_site parameters targeting login endpoints
• Implement file integrity monitoring on WordPress plugin directories to detect unauthorized uploads
• Review WordPress user session logs for authentication events that bypass normal login flows
• Deploy network intrusion detection rules to identify Metasploit framework traffic patterns associated with this exploit

Monitoring Recommendations

• Enable detailed logging for WordPress authentication events and plugin installation activities
• Configure alerting for any new administrator sessions originating from unexpected geographic locations or IP ranges
• Implement real-time monitoring of the wp-content/plugins/ directory for new file creation
• Review web server access logs for patterns consistent with automated exploitation attempts

How to Mitigate CVE-2025-34077

Immediate Actions Required

• Update the Pie Register plugin to the latest patched version immediately
• Audit WordPress user accounts for any unauthorized administrator accounts or suspicious activity
• Review recently installed or modified plugins and remove any unrecognized entries
• Rotate WordPress administrator credentials and invalidate all existing sessions
• Consider temporarily disabling the Pie Register plugin if an immediate update is not possible

Patch Information

Organizations should update the WordPress Pie Register plugin to a version newer than 3.7.1.4 that addresses this authentication bypass vulnerability. Plugin updates can be applied through the WordPress admin dashboard or by downloading the latest version from the WordPress Plugin Page. Additional technical details and security advisories are available through VulnCheck Advisory.

Workarounds

• Implement web application firewall rules to block POST requests containing social_site=true parameter to WordPress login endpoints
• Disable social login functionality in Pie Register plugin settings until a patch can be applied
• Restrict access to WordPress admin pages (/wp-admin/) to trusted IP addresses only
• Enable multi-factor authentication for all WordPress administrator accounts as an additional security layer
• Consider using WordPress security plugins that provide real-time monitoring and blocking of suspicious authentication attempts