CVE-2020-28140
📋 TL;DR
CVE-2020-28140 is a critical arbitrary file upload vulnerability in SourceCodester Online Clothing Store 1.0 that allows attackers to upload malicious files via the Products.php image upload feature. This affects all installations of version 1.0 of this PHP-based e-commerce software. Attackers can exploit this to achieve remote code execution and compromise the entire web server.
💻 Affected Systems
- SourceCodester Online Clothing Store
📦 What is this software?
Online Clothing Store by Online Clothing Store Project
⚠️ Risk & Real-World Impact
Worst Case
Full server compromise leading to data theft, ransomware deployment, lateral movement to other systems, and complete loss of confidentiality, integrity, and availability.
Likely Case
Remote code execution allowing attackers to deface websites, steal customer data, install backdoors, and use the server for malicious activities like cryptocurrency mining or phishing campaigns.
If Mitigated
Limited impact with proper file upload validation, restricted file permissions, and web application firewalls blocking malicious upload attempts.
🎯 Exploit Status
Exploit code is publicly available on Exploit-DB (48438) and requires minimal technical skill to execute. Attackers can upload PHP webshells directly.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: Not available
Restart Required: No
Instructions:
No official patch exists. The software appears abandoned. Recommended to replace with alternative e-commerce solutions or implement comprehensive workarounds.
🔧 Temporary Workarounds
Implement File Upload Validation
allAdd server-side validation to restrict uploaded files to specific extensions (jpg, png, gif) and verify MIME types.
Modify Products.php to include: $allowed_extensions = ['jpg', 'jpeg', 'png', 'gif']; $file_extension = strtolower(pathinfo($_FILES['image']['name'], PATHINFO_EXTENSION)); if (!in_array($file_extension, $allowed_extensions)) { die('Invalid file type'); }
Restrict Upload Directory Permissions
linuxSet upload directory permissions to prevent execution of uploaded files.
chmod 644 /path/to/upload/directory/*
chmod 755 /path/to/upload/directory/
Add to .htaccess in upload directory: php_flag engine off
🧯 If You Can't Patch
- Deploy a Web Application Firewall (WAF) with rules to block malicious file uploads and PHP execution attempts.
- Isolate the application in a restricted network segment with no internet access and implement strict outbound firewall rules.
🔍 How to Verify
Check if Vulnerable:
Attempt to upload a file with .php extension via the Products.php image upload feature. If successful, the system is vulnerable.Check Version:
Check the software version in admin panel or look for version markers in source code files.Verify Fix Applied:
Test file upload with various malicious extensions (.php, .phtml, .php5) - all should be rejected. Verify uploaded files cannot be executed.📡 Detection & Monitoring
Log Indicators:
- HTTP POST requests to Products.php with unusual file extensions
- Files with .php, .phtml, .php5 extensions appearing in upload directories
- Webshell access patterns in access logs
Network Indicators:
- Unusual outbound connections from web server
- Traffic patterns consistent with webshell communication
SIEM Query:
source="web_logs" AND (uri="/Products.php" AND method="POST" AND (file_extension="php" OR file_extension="phtml" OR file_extension="php5"))