CVE-2021-29393
📋 TL;DR
This vulnerability allows remote unauthenticated attackers to execute arbitrary system commands on NorthStar Club Management servers by injecting malicious commands into unsanitized parameters. It affects Northstar Technologies Inc NorthStar Club Management version 6.3, potentially compromising any server running this software.
💻 Affected Systems
- Northstar Technologies Inc NorthStar Club Management
📦 What is this software?
Northstar Club Management by Globalnorthstar
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise leading to data theft, ransomware deployment, lateral movement within the network, and persistent backdoor installation.
Likely Case
Attackers gain shell access to the server, steal sensitive club member data, install cryptocurrency miners, or use the server as a pivot point for further attacks.
If Mitigated
Limited impact if proper network segmentation, web application firewalls, and input validation are in place, though the vulnerability remains exploitable.
🎯 Exploit Status
Exploitation requires simple HTTP requests with command injection payloads. Public proof-of-concept code exists in security advisories.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown - Check with vendor for patched version
Vendor Advisory: https://ardent-security.com/en/advisory/asa-2021-01/
Restart Required: Yes
Instructions:
1. Contact Northstar Technologies for patched version. 2. Backup configuration and data. 3. Apply vendor-provided patch. 4. Restart application services. 5. Verify fix.
🔧 Temporary Workarounds
Web Application Firewall Rule
allBlock or sanitize requests containing shell metacharacters in command and commandvalues parameters
WAF specific - configure rules to block patterns like ;, |, &, $, (, ), `, >, < in parameters
Access Control Restriction
linuxRestrict access to cominput.jsp and comoutput.jsp endpoints using network controls
iptables -A INPUT -p tcp --dport 80 -m string --string "cominput.jsp" --algo bm -j DROP
iptables -A INPUT -p tcp --dport 80 -m string --string "comoutput.jsp" --algo bm -j DROP
🧯 If You Can't Patch
- Implement strict network segmentation to isolate the vulnerable system from critical assets
- Deploy a web application firewall with command injection detection rules in blocking mode
🔍 How to Verify
Check if Vulnerable:
Send HTTP GET request to /cominput.jsp?command=id&commandvalues=test and check if system command output appears in responseCheck Version:
Check application version in web interface or configuration filesVerify Fix Applied:
Attempt the same test after patching - should receive error or sanitized response without command execution📡 Detection & Monitoring
Log Indicators:
- Unusual POST/GET requests to cominput.jsp or comoutput.jsp with shell metacharacters
- System commands in URL parameters or POST data
- Multiple failed exploitation attempts
Network Indicators:
- HTTP requests containing shell commands like whoami, id, ls, cat, wget, curl in parameters
- Outbound connections from web server to unusual destinations
SIEM Query:
source="web_logs" AND (uri="*cominput.jsp*" OR uri="*comoutput.jsp*") AND (param="*;*" OR param="*|*" OR param="*&*" OR param="*`*")