CVE-2020-14072
📋 TL;DR
CVE-2020-14072 is a critical command injection vulnerability in MK-AUTH 19.01 that allows attackers to execute arbitrary commands as root via shell metacharacters in admin scripts. This affects all systems running the vulnerable version of MK-AUTH authentication software. Attackers can gain complete control over affected systems.
💻 Affected Systems
- MK-AUTH
📦 What is this software?
Mk Auth by Mk Auth
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with root privileges, allowing data theft, ransomware deployment, lateral movement, and persistent backdoor installation.
Likely Case
Remote code execution leading to web server compromise, credential harvesting, and installation of cryptocurrency miners or botnet malware.
If Mitigated
Limited impact with proper network segmentation, but still significant risk to the affected web server.
🎯 Exploit Status
Public proof-of-concept code is available on GitHub gist, making exploitation straightforward for attackers.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after 19.01 (check vendor changelog for specific fixed version)
Vendor Advisory: http://mk-auth.com.br/page/changelog-1
Restart Required: Yes
Instructions:
1. Backup current configuration. 2. Download latest version from vendor. 3. Replace vulnerable files. 4. Restart web service. 5. Verify fix.
🔧 Temporary Workarounds
Input Validation Filter
linuxImplement strict input validation to block shell metacharacters in admin script parameters
# Add input validation in affected PHP scripts to filter: ; & | ` $ ( ) [ ] { } < > \n \r \t
Access Restriction
linuxRestrict access to /auth admin scripts using web server configuration
# Apache: <Location /auth>\n Order deny,allow\n Deny from all\n Allow from trusted_ips\n</Location>
# Nginx: location /auth {\n deny all;\n allow trusted_ips;\n}
🧯 If You Can't Patch
- Implement strict network segmentation to isolate MK-AUTH systems from critical infrastructure
- Deploy web application firewall (WAF) with command injection protection rules
🔍 How to Verify
Check if Vulnerable:
Check if MK-AUTH version is 19.01 by examining version files or web interface. Test with safe command injection payloads in controlled environment.Check Version:
grep -r 'version\|Version' /path/to/mk-auth/installation/ | head -5Verify Fix Applied:
Verify version is updated beyond 19.01. Test that shell metacharacters in admin script parameters no longer execute commands.📡 Detection & Monitoring
Log Indicators:
- Unusual command execution in web server logs
- Shell metacharacters in URL parameters to /auth paths
- Unexpected processes spawned from web server user
Network Indicators:
- Unusual outbound connections from web server
- Command and control traffic patterns
SIEM Query:
source="web_logs" AND (url="/auth/*" AND (param="*;*" OR param="*&*" OR param="*|*" OR param="*`*"))