CVE-2024-9106: WeChat Social Login Auth Bypass Flaw

CVE-2024-9106 Overview

The Wechat Social login plugin for WordPress contains a critical authentication bypass vulnerability in versions up to and including 1.3.0. This flaw stems from insufficient verification of user identity during the social login process. When the app secret configuration is left empty (the default value), unauthenticated attackers can exploit this weakness to log in as any existing user on the site, including administrators, by simply knowing or guessing the target user's ID.

Critical Impact

Unauthenticated attackers can gain administrative access to WordPress sites using vulnerable Wechat Social login configurations with default empty app secret values.

Affected Products

• Wechat Social login plugin for WordPress versions up to and including 1.3.0
• WordPress installations with the vulnerable plugin installed and app secret not configured

Discovery Timeline

• 2024-10-01 - CVE-2024-9106 published to NVD
• 2024-10-04 - Last updated in NVD database

Technical Details for CVE-2024-9106

Vulnerability Analysis

This authentication bypass vulnerability (CWE-288: Authentication Bypass Using an Alternate Path or Channel) exists in the Wechat Social login plugin's social login implementation. The vulnerable code path is located in the class-xh-social-channel-qq.php file within the social-qq add-on module.

The core issue lies in how the plugin validates user identity during the social authentication flow. When processing login requests, the plugin fails to adequately verify that the user being authenticated is the legitimate owner of the social account credentials being presented. This verification gap becomes exploitable specifically when the app secret configuration option remains at its default empty value.

Under these conditions, an attacker can craft requests that bypass the normal authentication checks entirely. By providing a valid user ID for any account on the WordPress installation, the attacker can authenticate as that user without needing valid credentials. This effectively grants complete account takeover capabilities, with administrator accounts being particularly high-value targets.

Root Cause

The root cause is insufficient verification of user identity during the social login authentication flow combined with an insecure default configuration. The plugin does not enforce that the app secret be configured, leaving a default empty value that disables critical security checks. This creates an authentication bypass condition where user-supplied user IDs are trusted without proper validation against the social platform's authentication response.

Attack Vector

The attack is network-accessible and requires no prior authentication or user interaction. An attacker can exploit this vulnerability by:

1. Identifying a WordPress site using the vulnerable Wechat Social login plugin
2. Confirming or determining that the app secret is not configured (default empty value)
3. Discovering or enumerating valid user IDs on the target site (user ID 1 is typically the administrator)
4. Crafting a social login request that specifies the target user ID
5. Bypassing authentication to gain access as the targeted user account

The vulnerability resides in the QQ social login channel component of the plugin. The insufficient verification allows the attacker's request to be processed as a legitimate social login, granting them a valid WordPress session for the targeted user account.

Detection Methods for CVE-2024-9106

Indicators of Compromise

• Unusual login activity from accounts that typically use standard WordPress authentication
• Authentication events occurring without corresponding WeChat/QQ social platform authorization callbacks
• Multiple accounts experiencing unexpected logins within short timeframes
• Administrator account access from unfamiliar IP addresses or locations

Detection Strategies

• Monitor WordPress authentication logs for social login events that lack proper OAuth callback validation
• Implement alerting for administrator account logins via the Wechat Social login method
• Audit plugin configurations to identify installations with empty app secret values
• Review access logs for requests to the class-xh-social-channel-qq.php endpoint with suspicious parameters

Monitoring Recommendations

• Enable WordPress audit logging to capture all authentication events with full request details
• Configure SIEM rules to alert on social login authentication for privileged accounts
• Implement real-time monitoring of WordPress plugin directory for the presence of vulnerable versions
• Set up configuration drift detection to identify when security settings are modified or left at default values

How to Mitigate CVE-2024-9106

Immediate Actions Required

• Update the Wechat Social login plugin to a patched version if available
• Configure the app secret setting with a proper value to prevent exploitation
• If no patch is available and the plugin is not essential, consider temporarily disabling or removing it
• Audit all user accounts for unauthorized access and review recent login history
• Reset credentials for any accounts that may have been compromised

Patch Information

Organizations using the Wechat Social login plugin should check the WordPress WeChat Plugin Source for updates. Additionally, the Wordfence Vulnerability Analysis provides detailed information about this vulnerability and remediation guidance.

Workarounds

• Configure the app secret with a valid, non-empty value to activate proper authentication verification
• Restrict access to the WordPress login and social authentication endpoints using web application firewall rules
• Implement additional authentication factors for administrator accounts
• Consider disabling the QQ social login add-on if not required for business operations

# WordPress configuration audit - check for vulnerable plugin
wp plugin list --status=active | grep -i wechat

# Disable the vulnerable plugin temporarily if needed
wp plugin deactivate wechat-social-login

# Check plugin version
wp plugin get wechat-social-login --field=version