CVE-2025-41347
📋 TL;DR
This vulnerability allows unauthenticated attackers to upload dangerous files (like webshells) to WinPlus Portal servers via a specific API endpoint. Attackers can achieve remote code execution and full system compromise. All organizations running vulnerable WinPlus v24.11.27 installations are affected.
💻 Affected Systems
- WinPlus Portal from Informática del Este
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system takeover with persistent backdoor installation, data exfiltration, lateral movement across network, and ransomware deployment.
Likely Case
Webshell upload leading to remote code execution, data theft, and potential pivot to internal systems.
If Mitigated
Attack blocked at WAF/web application firewall level with file upload restrictions; limited to attempted exploitation logs.
🎯 Exploit Status
Simple HTTP POST request with malicious file payload; no authentication required.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: https://www.incibe.es/en/incibe-cert/notices/aviso/stored-cross-site-scripting-xss-winplus-informatica-del-este
Restart Required: No
Instructions:
Contact Informática del Este for patch information; monitor vendor communications for updates.
🔧 Temporary Workarounds
Block vulnerable endpoint at WAF
allConfigure web application firewall to block POST requests to '/WinplusPortal/ws/sWinplus.svc/json/uploadfile'
WAF-specific configuration commands
Restrict file upload types
allImplement server-side validation to reject dangerous file extensions (.php, .jsp, .asp, .aspx, etc.)
Application-specific configuration
🧯 If You Can't Patch
- Isolate WinPlus servers in restricted network segment with no internet access
- Implement strict network monitoring and alerting for suspicious upload activity to the vulnerable endpoint
🔍 How to Verify
Check if Vulnerable:
Attempt to upload a test file (non-malicious) via POST to '/WinplusPortal/ws/sWinplus.svc/json/uploadfile' endpoint; if successful without proper validation, system is vulnerable.Check Version:
Check WinPlus Portal version in application interface or configuration filesVerify Fix Applied:
Test file upload with dangerous extensions; should be rejected with proper error messages.📡 Detection & Monitoring
Log Indicators:
- HTTP POST requests to '/WinplusPortal/ws/sWinplus.svc/json/uploadfile' with suspicious file extensions
- Unusual file creation in web directories
Network Indicators:
- POST requests to vulnerable endpoint with file uploads
- Subsequent connections to uploaded webshell files
SIEM Query:
source="web_server" AND (uri="/WinplusPortal/ws/sWinplus.svc/json/uploadfile" AND method="POST")