CVE-2020-19028
📋 TL;DR
This vulnerability allows remote attackers to upload arbitrary files via the /admin/plugin.php endpoint in EmlogCMS v6.0.0. Attackers can gain unauthorized access to sensitive information or potentially execute malicious code. All users running the vulnerable version are affected.
💻 Affected Systems
- EmlogCMS
📦 What is this software?
Emlog by Emlog
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, data theft, and lateral movement within the network.
Likely Case
Unauthorized file upload allowing attackers to place web shells, deface websites, or steal sensitive configuration files.
If Mitigated
Limited impact with proper file upload validation and access controls in place.
🎯 Exploit Status
Exploitation requires admin authentication but is straightforward once authenticated.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v6.0.1 or later
Vendor Advisory: https://github.com/emlog/emlog
Restart Required: No
Instructions:
1. Backup your EmlogCMS installation and database. 2. Download the latest version from the official repository. 3. Replace all files except config.php and uploads directory. 4. Verify the update completed successfully.
🔧 Temporary Workarounds
Restrict Admin Access
allLimit access to the admin interface using IP whitelisting or VPN.
# Example: Apache .htaccess
Order Deny,Allow
Deny from all
Allow from 192.168.1.0/24
Disable Plugin Upload
linuxTemporarily disable the plugin.php functionality or restrict file uploads.
# Rename or move plugin.php
mv admin/plugin.php admin/plugin.php.disabled
🧯 If You Can't Patch
- Implement strict file upload validation and sanitization in the plugin.php file.
- Deploy a web application firewall (WAF) with rules to block malicious file upload attempts.
🔍 How to Verify
Check if Vulnerable:
Check if running EmlogCMS v6.0.0 by examining the version in the admin panel or source code.Check Version:
grep -r 'EMLOG_VERSION' includes/ || cat data/config.php | grep versionVerify Fix Applied:
Verify the version is updated to v6.0.1 or later and test file upload functionality with malicious files.📡 Detection & Monitoring
Log Indicators:
- Unusual file uploads to /admin/plugin.php
- Multiple failed authentication attempts followed by successful login
Network Indicators:
- HTTP POST requests to /admin/plugin.php with file uploads
- Traffic patterns indicating web shell communication
SIEM Query:
source="web_logs" AND uri="/admin/plugin.php" AND method="POST" AND (file_extension="php" OR file_extension="jsp" OR file_extension="asp")