CVE-2021-3029
📋 TL;DR
CVE-2021-3029 is a critical OS command injection vulnerability in EVOLUCARE ECSIMAGING software that allows attackers to execute arbitrary commands with root privileges by exploiting the 'file' parameter on /showfile.php. This affects all versions through 6.21.5, but only impacts products no longer supported by the vendor.
💻 Affected Systems
- EVOLUCARE ECSIMAGING (ECS Imaging)
📦 What is this software?
Ecs Imaging by Evolucare
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with root access, allowing data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Remote code execution leading to data exfiltration, lateral movement within the network, or cryptomining malware installation.
If Mitigated
Limited impact if proper network segmentation and web application firewalls block exploitation attempts.
🎯 Exploit Status
Exploitation is straightforward using shell metacharacters and IFS manipulation. Public proof-of-concept demonstrates root access achievement.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: None - product is end-of-life
Vendor Advisory: https://www.evolucare.com
Restart Required: No
Instructions:
No official patch exists. Consider migrating to supported alternatives or implementing strict compensating controls.
🔧 Temporary Workarounds
Web Application Firewall Rule
allBlock or sanitize malicious input to the 'file' parameter using WAF rules
# Example ModSecurity rule: SecRule ARGS:file "[;|&`$()]" "id:1001,phase:2,deny,status:403"
Access Restriction
linuxRestrict access to /showfile.php endpoint using network controls
# Apache: <Location /showfile.php> Require ip 10.0.0.0/8 </Location>
# Nginx: location /showfile.php { allow 10.0.0.0/8; deny all; }
🧯 If You Can't Patch
- Immediately isolate affected systems from internet access and restrict to minimal necessary network connectivity
- Implement strict input validation and sanitization for all user-supplied parameters in the application
🔍 How to Verify
Check if Vulnerable:
Test if /showfile.php endpoint accepts shell metacharacters in the 'file' parameter. Example: curl 'http://target/showfile.php?file=test;id'Check Version:
Check application version in web interface or configuration files. Typically found in /var/www/ecsimaging/ or similar web root.Verify Fix Applied:
Verify WAF rules block malicious requests or that endpoint is no longer accessible. Test with same exploitation attempts.📡 Detection & Monitoring
Log Indicators:
- Unusual commands in web server logs containing ;, |, &, `, $, or () in file parameter
- Multiple rapid requests to /showfile.php with varying parameters
- Web server process spawning unexpected child processes
Network Indicators:
- HTTP requests to /showfile.php with shell metacharacters in parameters
- Outbound connections from web server to unexpected destinations
SIEM Query:
source="web_server" AND uri="/showfile.php" AND (param="*;*" OR param="*|*" OR param="*&*" OR param="*`*" OR param="*$(*)*")