CVE-2021-46076
📋 TL;DR
This vulnerability allows unauthenticated attackers to upload malicious PHP files to the Vehicle Service Management System 1.0, leading to remote code execution. Attackers can take full control of affected systems, potentially compromising sensitive data and infrastructure. Organizations using this specific software version are at risk.
💻 Affected Systems
- Sourcecodester Vehicle Service Management System
📦 What is this software?
Vehicle Service Management System by Vehicle Service Management System Project
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attackers to execute arbitrary code, steal sensitive data, install backdoors, pivot to other systems, and potentially disrupt operations.
Likely Case
Attackers upload web shells to gain persistent access, exfiltrate database contents containing customer/service records, and use the system as a foothold for further attacks.
If Mitigated
With proper file upload restrictions and web application firewalls, the attack surface is reduced, though the fundamental vulnerability remains until patched.
🎯 Exploit Status
Multiple public proof-of-concept exploits exist, and the attack requires minimal technical skill. The vulnerability is actively exploited in the wild.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: Not available
Restart Required: No
Instructions:
1. Check for official vendor patches (none available as of analysis). 2. Consider replacing with alternative software. 3. If continuing use, implement all workarounds below.
🔧 Temporary Workarounds
Restrict File Upload Types
allConfigure web server to block PHP file uploads and only allow specific safe file types
# Apache: Add to .htaccess
<FilesMatch "\.(php|php3|php4|php5|phtml|pl|cgi)">
Order Deny,Allow
Deny from all
</FilesMatch>
# Nginx: Add to server block
location ~ \.php$ {
deny all;
}
Implement Web Application Firewall
allDeploy WAF rules to block malicious file upload patterns
# ModSecurity rule example
SecRule FILES_TMPNAMES "@rx \.php$" "id:1001,phase:2,deny,msg:'PHP file upload attempt'"
🧯 If You Can't Patch
- Isolate the system in a restricted network segment with no internet access
- Implement strict file upload validation at the application layer, rejecting all executable files
🔍 How to Verify
Check if Vulnerable:
Attempt to upload a test PHP file to endpoints like /upload.php or similar upload functionality. If accepted without validation, system is vulnerable.Check Version:
Check application files for version information, typically in README, configuration files, or admin panelVerify Fix Applied:
Test that PHP files are rejected during upload attempts and that existing PHP files in upload directories cannot be executed.📡 Detection & Monitoring
Log Indicators:
- Multiple failed/successful file upload attempts with .php extension
- Unusual POST requests to upload endpoints
- Execution of uploaded files from unusual locations
Network Indicators:
- HTTP POST requests with PHP file content to upload endpoints
- Subsequent requests to uploaded PHP files
SIEM Query:
source="web_server" (method="POST" uri_path="*upload*" AND (file_extension="php" OR content_type="application/x-php"))🔗 References
- https://github.com/plsanu/Vehicle-Service-Management-System-Multiple-File-upload-Leads-to-Code-Execution
- https://www.plsanu.com/vehicle-service-management-system-multiple-file-upload-leads-to-code-execution
- https://github.com/plsanu/Vehicle-Service-Management-System-Multiple-File-upload-Leads-to-Code-Execution
- https://www.plsanu.com/vehicle-service-management-system-multiple-file-upload-leads-to-code-execution
