CVE-2020-13569
📋 TL;DR
This CSRF vulnerability in OpenEMR's GACL functionality allows attackers to trick authenticated users into performing unintended actions by sending specially crafted HTTP requests. It affects OpenEMR 5.0.2 and development version 6.0.0, potentially enabling attackers to execute arbitrary requests with the victim's privileges.
💻 Affected Systems
- OpenEMR
📦 What is this software?
Openemr by Open Emr
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of the OpenEMR system, allowing attackers to modify patient records, access sensitive health data, or execute administrative functions as the victim user.
Likely Case
Unauthorized modification of patient data, configuration changes, or privilege escalation within the OpenEMR application.
If Mitigated
Limited impact with proper CSRF protections, same-origin policies, and user awareness training in place.
🎯 Exploit Status
Exploitation requires the victim to be authenticated and visit a malicious page while logged into OpenEMR.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: OpenEMR 5.0.2.1 and later versions
Vendor Advisory: https://www.open-emr.org/wiki/index.php/OpenEMR_Patches
Restart Required: No
Instructions:
1. Update to OpenEMR 5.0.2.1 or later. 2. Apply CSRF protection tokens to all GACL-related forms and endpoints. 3. Verify the fix by testing GACL functionality with CSRF testing tools.
🔧 Temporary Workarounds
Implement CSRF Protection Headers
allAdd SameSite cookie attributes and CSRF tokens to mitigate attack surface
Set-Cookie: session=value; SameSite=Strict; Secure; HttpOnly
Restrict GACL Access
allLimit access to GACL functionality to administrative users only
Modify OpenEMR ACL configuration to restrict GACL module access
🧯 If You Can't Patch
- Implement web application firewall (WAF) rules to detect and block CSRF patterns
- Educate users about CSRF risks and safe browsing practices when accessing OpenEMR
🔍 How to Verify
Check if Vulnerable:
Check OpenEMR version via admin interface or by examining source code version markers. If running 5.0.2 or development version 6.0.0 with vulnerable commit, system is vulnerable.Check Version:
Check OpenEMR version in admin interface or examine /sites/default/sqlconf.php for version informationVerify Fix Applied:
Test GACL functionality with CSRF testing tools like OWASP ZAP or Burp Suite to confirm CSRF tokens are properly implemented.📡 Detection & Monitoring
Log Indicators:
- Multiple GACL-related requests from same user in short timeframe
- GACL modifications from unexpected IP addresses or user agents
Network Indicators:
- HTTP POST requests to GACL endpoints without proper referrer headers or CSRF tokens
- Cross-origin requests to OpenEMR GACL functionality
SIEM Query:
source="openemr" AND (uri_path="*gacl*" OR uri_path="*acl*") AND http_method="POST" AND NOT (referrer="*openemr*")