CVE-2019-8158
📋 TL;DR
This vulnerability allows attackers to perform XPath entity injection via crafted GET requests to Magento's page cache block rendering module. It affects Magento 2.2 and 2.3 installations, potentially exposing underlying XML data to unauthorized access.
💻 Affected Systems
- Magento Commerce
- Magento Open Source
📦 What is this software?
Magento by Magento
Magento by Magento
Magento by Magento
Magento by Magento
Magento by Magento
Magento by Magento
⚠️ Risk & Real-World Impact
Worst Case
Attackers could extract sensitive data from XML files, potentially including configuration data, user information, or other system details stored in XML format.
Likely Case
Limited data exposure from XML files accessible to the application, potentially revealing configuration details or partial data structures.
If Mitigated
With proper input validation and XML parsing restrictions, impact is limited to error generation or no access to sensitive data.
🎯 Exploit Status
Exploitation requires crafting specific GET requests to vulnerable endpoints, which is relatively straightforward for attackers with basic web application testing knowledge.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Magento 2.2.10, Magento 2.3.3, or Magento 2.3.2-p1
Vendor Advisory: https://magento.com/security/patches/magento-2.3.3-and-2.2.10-security-update
Restart Required: Yes
Instructions:
1. Backup your Magento installation and database. 2. Update Magento via Composer: composer require magento/product-community-edition=2.3.3 --no-update. 3. Run composer update. 4. Clear cache: php bin/magento cache:clean. 5. Deploy static content: php bin/magento setup:static-content:deploy. 6. Restart web server.
🔧 Temporary Workarounds
Input Validation Filter
allImplement custom input validation to filter or reject suspicious GET parameters containing XML entity references.
Implement in application code - no single command
🧯 If You Can't Patch
- Implement WAF rules to block requests containing XML entity injection patterns in GET parameters
- Restrict access to page cache rendering endpoints via network ACLs or authentication requirements
🔍 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:
Confirm version is 2.2.10, 2.3.3, or 2.3.2-p1 or higher, and test with known exploit patterns that should be blocked.📡 Detection & Monitoring
Log Indicators:
- Unusual GET requests with XML-like parameters to cache-related endpoints
- Errors in application logs related to XML parsing failures
Network Indicators:
- HTTP GET requests containing %3C, %3E, %26, or other XML entity encodings in parameter values
SIEM Query:
web_access_logs | where url contains "page_cache/block/render" and (url contains "%3C" or url contains "%3E" or url contains "%26")