CVE-2023-5256
📋 TL;DR
Drupal's JSON:API module can expose sensitive error backtraces that may be cached and accessible to anonymous users. This information disclosure vulnerability could lead to privilege escalation by revealing system details. Only sites with the JSON:API module enabled are affected.
💻 Affected Systems
- Drupal
📦 What is this software?
Drupal by Drupal
Drupal by Drupal
Drupal by Drupal
⚠️ Risk & Real-World Impact
Worst Case
Anonymous users obtain sensitive system information from cached error backtraces, enabling privilege escalation attacks that could lead to full site compromise.
Likely Case
Anonymous users access cached error information containing system paths, configuration details, or other sensitive data that could aid further attacks.
If Mitigated
With proper caching controls and error handling, only generic error messages are exposed, limiting information disclosure.
🎯 Exploit Status
Exploitation requires triggering error conditions in JSON:API endpoints and accessing cached error responses.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Apply Drupal security update for CVE-2023-5256
Vendor Advisory: https://www.drupal.org/sa-core-2023-006
Restart Required: No
Instructions:
1. Update Drupal core to the latest secure version. 2. Apply the security patch for CVE-2023-5256. 3. Clear all caches after patching.
🔧 Temporary Workarounds
Disable JSON:API Module
allUninstall the JSON:API module to completely mitigate the vulnerability
drush pm-uninstall jsonapi
Configure Error Handling
allConfigure Drupal to not display error backtraces to users
Set $config['system.logging']['error_level'] = 'hide' in settings.php
🧯 If You Can't Patch
- Disable the JSON:API module immediately
- Implement strict caching controls to prevent caching of error responses
🔍 How to Verify
Check if Vulnerable:
Check if JSON:API module is enabled and review error handling configurationCheck Version:
drush status | grep 'Drupal version'Verify Fix Applied:
Verify Drupal core is updated to patched version and test JSON:API error responses📡 Detection & Monitoring
Log Indicators:
- Multiple error responses from JSON:API endpoints
- Anonymous users accessing cached error pages
Network Indicators:
- Unusual requests to JSON:API endpoints designed to trigger errors
SIEM Query:
source="drupal" AND (uri="*jsonapi*" AND status>=500)