CVE-2025-29281
📋 TL;DR
PerfreeBlog 4.0.11 contains an arbitrary file upload vulnerability in the attach component that allows regular users to upload malicious files and execute code. This enables remote code execution (RCE) on affected systems. All deployments running the vulnerable version are at risk.
💻 Affected Systems
- PerfreeBlog
📦 What is this software?
Perfreeblog by Perfree
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining complete control over the web server, data exfiltration, lateral movement, and persistent backdoor installation.
Likely Case
Attacker uploads web shell to gain persistent access, deface website, steal sensitive data, or use server for cryptocurrency mining or botnet activities.
If Mitigated
If proper file upload restrictions and user authentication controls are in place, impact is limited to unauthorized file storage but not code execution.
🎯 Exploit Status
Exploitation requires authenticated user access. The GitHub reference shows proof-of-concept details. Weaponization is likely due to the straightforward nature of file upload vulnerabilities.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Unknown
Restart Required: No
Instructions:
1. Monitor PerfreeBlog official channels for security updates. 2. Check GitHub repository for patches. 3. Apply any available security patches immediately. 4. Consider upgrading to a newer version if available.
🔧 Temporary Workarounds
Disable Attach Component
allTemporarily disable the vulnerable attach component to prevent exploitation
# Modify PerfreeBlog configuration to disable file upload functionality
# Check configuration files for upload settings
Web Server File Upload Restrictions
linuxConfigure web server (Apache/Nginx) to block uploads to vulnerable paths
# Apache: <Location /path/to/attach>
Deny from all
</Location>
# Nginx: location /path/to/attach { deny all; }
🧯 If You Can't Patch
- Implement strict file upload validation: allow only specific file types, enforce size limits, and scan uploaded files
- Restrict user permissions: ensure regular users cannot access or execute uploaded files in web-accessible directories
🔍 How to Verify
Check if Vulnerable:
Check if running PerfreeBlog version 4.0.11. Review application logs for suspicious file uploads to attach component.Check Version:
# Check PerfreeBlog version in admin panel or configuration filesVerify Fix Applied:
Test file upload functionality with malicious files to ensure they are rejected. Verify version is no longer 4.0.11.📡 Detection & Monitoring
Log Indicators:
- Unusual file uploads to attach component
- Uploads of executable files (php, jsp, asp)
- Multiple failed upload attempts
- Files with suspicious names or extensions
Network Indicators:
- POST requests to /attach endpoint with file uploads
- Unusual outbound connections from web server
SIEM Query:
source="web_logs" AND (uri_path="/attach" OR uri_path CONTAINS "upload") AND (file_extension="php" OR file_extension="jsp" OR file_extension="asp")