CVE-2021-31316
📋 TL;DR
This SQL injection vulnerability in CentOS Web Panel's unprivileged user portal allows attackers to execute arbitrary SQL commands via the 'idsession' parameter. Successful exploitation can lead to remote code execution with root privileges. All CentOS Web Panel installations with the vulnerable component are affected.
💻 Affected Systems
- CentOS Web Panel (CWP)
📦 What is this software?
Webpanel by Control Webpanel
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with root-level remote code execution, allowing complete control over the server, data theft, and lateral movement.
Likely Case
Database compromise leading to credential theft, data exfiltration, and potential privilege escalation to root via subsequent exploitation.
If Mitigated
Limited impact with proper input validation, WAF protection, and network segmentation preventing successful exploitation.
🎯 Exploit Status
Public exploit code is available and requires no authentication. The vulnerability is easily weaponized due to simple SQL injection.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.9.8.1147 and later
Vendor Advisory: https://centos-webpanel.com/changelog-cwp7
Restart Required: No
Instructions:
1. Update CentOS Web Panel using the built-in updater or command line. 2. Run: /scripts/update_cwp 3. Verify the version is 0.9.8.1147 or higher.
🔧 Temporary Workarounds
WAF Rule Implementation
linuxDeploy web application firewall rules to block SQL injection patterns in the idsession parameter.
# Example ModSecurity rule: SecRule ARGS:idsession "@detectSQLi" "id:1001,phase:2,deny"
Input Validation Filter
linuxAdd input validation to sanitize the idsession parameter before processing.
# Example PHP filter: $idsession = preg_replace('/[^a-zA-Z0-9]/', '', $_POST['idsession']);
🧯 If You Can't Patch
- Block external access to the CentOS Web Panel user portal using firewall rules.
- Implement network segmentation to isolate the CWP server from critical systems.
🔍 How to Verify
Check if Vulnerable:
Check if the CWP version is below 0.9.8.1147 by accessing the panel interface or checking the version file.Check Version:
cat /usr/local/cwpsrv/var/services/version.txtVerify Fix Applied:
Confirm the version is 0.9.8.1147 or higher and test that SQL injection attempts are blocked.📡 Detection & Monitoring
Log Indicators:
- Unusual SQL queries in application logs
- Multiple failed login attempts with SQL patterns in idsession
Network Indicators:
- HTTP POST requests to user portal with SQL injection payloads in idsession parameter
SIEM Query:
source="web_logs" AND uri="/login/index.php" AND POST_param="idsession" AND (payload="' OR " OR payload="UNION" OR payload="SELECT")