CVE-2021-26683
📋 TL;DR
This CVE describes a remote authenticated command injection vulnerability in Aruba ClearPass Policy Manager. Authenticated attackers can execute arbitrary commands as root on the underlying operating system, leading to complete system compromise. Affected versions include ClearPass Policy Manager prior to 6.9.5, 6.8.8-HF1, and 6.7.14-HF1.
💻 Affected Systems
- Aruba ClearPass Policy Manager
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with root-level access, allowing data theft, lateral movement, persistence, and full control of the ClearPass system.
Likely Case
Attackers with valid credentials gain full administrative control over the ClearPass system, potentially compromising network authentication and policy enforcement.
If Mitigated
With proper network segmentation and credential protection, impact is limited to the ClearPass system itself.
🎯 Exploit Status
Exploitation requires valid credentials but command injection is typically straightforward once authenticated.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 6.9.5, 6.8.8-HF1, or 6.7.14-HF1
Vendor Advisory: https://www.arubanetworks.com/assets/alert/ARUBA-PSA-2021-004.txt
Restart Required: Yes
Instructions:
1. Download appropriate patch version from Aruba support portal. 2. Backup current configuration. 3. Apply patch following Aruba's upgrade documentation. 4. Restart ClearPass services.
🔧 Temporary Workarounds
Network Access Restriction
allRestrict access to ClearPass management interface to trusted IP addresses only.
Credential Hardening
allImplement strong password policies, multi-factor authentication, and regular credential rotation for all administrative accounts.
🧯 If You Can't Patch
- Isolate ClearPass system in a dedicated network segment with strict firewall rules.
- Implement network-based intrusion detection/prevention systems to monitor for command injection patterns.
🔍 How to Verify
Check if Vulnerable:
Check ClearPass version via web interface: Admin > Support > System Information, or CLI: show versionCheck Version:
show versionVerify Fix Applied:
Verify version is 6.9.5, 6.8.8-HF1, or 6.7.14-HF1 or later.📡 Detection & Monitoring
Log Indicators:
- Unusual command execution patterns in system logs
- Multiple failed authentication attempts followed by successful login
- Unexpected process execution from web interface user context
Network Indicators:
- Unusual outbound connections from ClearPass system
- Command injection patterns in HTTP requests to management interface
SIEM Query:
source="clearpass" AND (event_type="command_execution" OR http_uri="*;*" OR http_uri="*|*" OR http_uri="*`*" OR http_uri="*$(*")