CVE-2021-21013
📋 TL;DR
This CVE describes an Insecure Direct Object Reference (IDOR) vulnerability in Magento's customer API module. Attackers can access or modify other users' account information without proper authorization. Affected systems include Magento 2.4.1 and earlier, 2.4.0-p1 and earlier, and 2.3.6 and earlier.
💻 Affected Systems
- Adobe Magento Commerce
- Adobe Magento Open Source
📦 What is this software?
Magento by Adobe
Magento (now Adobe Commerce) is a leading open-source e-commerce platform powering hundreds of thousands of online stores worldwide, processing billions in transactions across B2C, B2B, and marketplace models. Used by brands including Nike, Ford, Coca-Cola, Olympus, and thousands of mid-market retai...
Learn more about Magento →Magento by Adobe
Magento (now Adobe Commerce) is a leading open-source e-commerce platform powering hundreds of thousands of online stores worldwide, processing billions in transactions across B2C, B2B, and marketplace models. Used by brands including Nike, Ford, Coca-Cola, Olympus, and thousands of mid-market retai...
Learn more about Magento →⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of customer data including personal information, payment details, and ability to modify orders or account settings for all users.
Likely Case
Unauthorized access to customer profiles, exposure of personal information, and potential account takeover for targeted users.
If Mitigated
Limited impact with proper API authentication and authorization controls, potentially only affecting users with weak session management.
🎯 Exploit Status
Exploitation requires API access but is straightforward once authenticated. IDOR vulnerabilities are commonly exploited in the wild.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Magento 2.4.2, 2.4.1-p1, 2.3.7
Vendor Advisory: https://helpx.adobe.com/security/products/magento/apsb21-08.html
Restart Required: Yes
Instructions:
1. Backup your Magento installation and database. 2. Update to Magento 2.4.2, 2.4.1-p1, or 2.3.7 using the standard Magento update process. 3. Clear cache and reindex. 4. Verify the update was successful.
🔧 Temporary Workarounds
Disable Customer API Module
allTemporarily disable the vulnerable customer API module until patching is possible.
php bin/magento module:disable Magento_Customer
Restrict API Access
allImplement IP whitelisting or additional authentication layers for API endpoints.
Configure web server (Apache/Nginx) to restrict access to /rest/* endpoints
🧯 If You Can't Patch
- Implement strict API authentication with multi-factor authentication
- Deploy a Web Application Firewall (WAF) with IDOR protection rules
🔍 How to Verify
Check if Vulnerable:
Check Magento version via admin panel or run: php bin/magento --versionCheck Version:
php bin/magento --versionVerify Fix Applied:
Verify version is 2.4.2, 2.4.1-p1, or 2.3.7 or later. Test API endpoints for proper authorization checks.📡 Detection & Monitoring
Log Indicators:
- Unusual API access patterns
- Multiple failed authorization attempts on customer endpoints
- API requests accessing customer IDs not belonging to the authenticated user
Network Indicators:
- Unusual traffic to /rest/V1/customers/* endpoints
- API requests with sequential or brute-forced customer IDs
SIEM Query:
source="magento_access.log" AND (uri_path="/rest/V1/customers/*" AND NOT user_agent="legitimate_bot") | stats count by src_ip, uri_path