CVE-2021-37214
📋 TL;DR
This CVE describes an Insecure Direct Object Reference (IDOR) vulnerability in Flygo's employee management page. Authenticated general users can manipulate employee IDs to access, modify data, escalate to administrator privileges, and execute arbitrary commands. Organizations using vulnerable Flygo versions are affected.
💻 Affected Systems
- Flygo
📦 What is this software?
Flygo by Larvata
⚠️ Risk & Real-World Impact
Worst Case
Attackers gain full administrative control, execute arbitrary commands on the system, access all employee data, and potentially compromise the entire Flygo deployment and connected systems.
Likely Case
Unauthorized access to sensitive employee data, privilege escalation to administrator, and potential data manipulation or exfiltration.
If Mitigated
Limited to unauthorized data viewing if proper access controls and input validation are implemented.
🎯 Exploit Status
Exploitation requires authenticated access but involves simple parameter manipulation; privilege escalation and RCE make it attractive for attackers.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not specified in provided references; check vendor advisory for specific version.
Vendor Advisory: https://www.twcert.org.tw/tw/cp-132-4991-658b1-1.html
Restart Required: Yes
Instructions:
1. Check the vendor advisory for patch details. 2. Apply the latest security update from Flygo. 3. Restart the application/service. 4. Verify the fix by testing parameter manipulation.
🔧 Temporary Workarounds
Implement Access Control Checks
allAdd server-side authorization checks to verify users can only access their own employee data.
Use Indirect Object References
allReplace direct object references with indirect references or tokens that cannot be easily manipulated.
🧯 If You Can't Patch
- Implement web application firewall (WAF) rules to block suspicious parameter manipulation in employee management requests.
- Restrict network access to Flygo to trusted IPs only and monitor for unusual authentication or privilege escalation patterns.
🔍 How to Verify
Check if Vulnerable:
As an authenticated general user, attempt to access or modify employee data by manipulating employee ID parameters in requests to the employee management page.Check Version:
Check Flygo application version via admin interface or configuration files; specific command depends on deployment.Verify Fix Applied:
After patching, repeat the vulnerability test; successful access controls should prevent unauthorized data access or modification.📡 Detection & Monitoring
Log Indicators:
- Unusual access patterns to employee data by non-admin users
- Multiple failed authorization attempts followed by successful data access
- Log entries showing privilege escalation from general to admin user.
Network Indicators:
- HTTP requests with manipulated employee ID parameters to employee management endpoints
- Sudden spikes in data access from single user accounts.
SIEM Query:
Example: source="flygo_logs" AND (event="data_access" AND user_role="general" AND resource="employee_data") OR (event="privilege_change" AND new_role="admin")