CVE-2021-40998
📋 TL;DR
This CVE describes a remote arbitrary command execution vulnerability in Aruba ClearPass Policy Manager. Attackers can execute arbitrary commands on affected systems, potentially gaining full control. Organizations running ClearPass Policy Manager versions 6.8.x, 6.9.x, or 6.10.x without the specified patches are affected.
💻 Affected Systems
- Aruba ClearPass Policy Manager
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attackers to execute arbitrary commands, steal sensitive data, deploy ransomware, pivot to other network segments, and maintain persistent access.
Likely Case
Attackers gain administrative access to ClearPass Policy Manager, potentially compromising network authentication systems, stealing credentials, and disrupting network access control.
If Mitigated
Limited impact with proper network segmentation, minimal exposure, and strong authentication controls preventing lateral movement.
🎯 Exploit Status
The vulnerability allows remote command execution without authentication, making it highly dangerous. While no public PoC is confirmed, the low complexity suggests exploitation is straightforward.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: ClearPass Policy Manager 6.10.2, 6.9.7-HF1, or 6.8.9-HF1
Vendor Advisory: https://www.arubanetworks.com/assets/alert/ARUBA-PSA-2021-018.txt
Restart Required: Yes
Instructions:
1. Download the appropriate patch from Aruba support portal. 2. Backup ClearPass configuration and data. 3. Apply the patch following Aruba's upgrade documentation. 4. Restart the ClearPass appliance. 5. Verify successful upgrade and functionality.
🔧 Temporary Workarounds
Network Access Control
linuxRestrict network access to ClearPass Policy Manager to only trusted IP addresses and networks.
iptables -A INPUT -p tcp --dport 443 -s trusted_network -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -j DROP
Web Application Firewall
allDeploy a WAF with command injection protection rules to block exploitation attempts.
🧯 If You Can't Patch
- Isolate the ClearPass appliance in a dedicated network segment with strict firewall rules
- Implement multi-factor authentication and monitor for suspicious authentication attempts
🔍 How to Verify
Check if Vulnerable:
Check ClearPass version via web interface (Administration > Support > System Information) or CLI command 'show version'Check Version:
show versionVerify Fix Applied:
Verify version is 6.10.2, 6.9.7-HF1, or 6.8.9-HF1 or later. Test functionality of all ClearPass services.📡 Detection & Monitoring
Log Indicators:
- Unusual command execution in system logs
- Authentication failures followed by successful access
- Unexpected process creation
Network Indicators:
- Unusual outbound connections from ClearPass appliance
- Traffic to unexpected ports or IP addresses
SIEM Query:
source="clearpass" AND (event_type="command_execution" OR process_name="sh" OR process_name="bash")