CVE-2025-9400
📋 TL;DR
This vulnerability in YiFang CMS allows remote attackers to upload arbitrary files without restrictions through the mergeMultipartUpload function. It affects all installations of YiFang CMS up to version 2.0.5, potentially enabling attackers to upload malicious files like webshells or backdoors.
💻 Affected Systems
- YiFang CMS
📦 What is this software?
Yifang by Wanglongcn
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, and lateral movement within the network.
Likely Case
Attackers upload webshells to gain persistent access, deface websites, or use the server for malicious activities.
If Mitigated
File uploads are blocked or properly validated, preventing malicious file execution.
🎯 Exploit Status
Proof of concept exploit is publicly available, making exploitation straightforward for attackers.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: None - vendor did not respond to disclosure
Restart Required: No
Instructions:
No official patch available. Consider upgrading if vendor releases fixed version, or implement workarounds.
🔧 Temporary Workarounds
Implement File Upload Validation
allAdd server-side validation to restrict file uploads to specific extensions and scan for malicious content.
Modify P_file.php to validate file extensions and content before processing
Disable File Upload Functionality
allTemporarily disable the vulnerable mergeMultipartUpload function if not essential.
Comment out or remove the mergeMultipartUpload function in P_file.php
🧯 If You Can't Patch
- Implement web application firewall (WAF) rules to block suspicious file upload patterns
- Restrict network access to YiFang CMS instances and monitor for unusual file upload activity
🔍 How to Verify
Check if Vulnerable:
Check if YiFang CMS version is 2.0.5 or earlier and if P_file.php contains the vulnerable mergeMultipartUpload function.Check Version:
Check YiFang CMS configuration files or admin panel for version informationVerify Fix Applied:
Test file upload functionality with restricted extensions; attempt to upload malicious files should be blocked.📡 Detection & Monitoring
Log Indicators:
- Unusual file uploads to app/utils/base/plugin/P_file.php
- Files with suspicious extensions (.php, .jsp, .asp) being uploaded
Network Indicators:
- HTTP POST requests to file upload endpoints with unusual payloads
SIEM Query:
source="web_server" AND (uri="/app/utils/base/plugin/P_file.php" OR file_upload="true") AND (file_extension="php" OR file_extension="jsp" OR file_extension="asp")