CVE-2021-37736
📋 TL;DR
This CVE describes a remote authentication bypass vulnerability in Aruba ClearPass Policy Manager that allows attackers to bypass authentication mechanisms and gain unauthorized access. Affected organizations are those running ClearPass Policy Manager versions 6.8.x prior to 6.8.9-HF1, 6.9.x prior to 6.9.7-HF1, or 6.10.x prior to 6.10.2.
💻 Affected Systems
- Aruba ClearPass Policy Manager
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Attackers gain administrative access to ClearPass Policy Manager, potentially compromising the entire network authentication infrastructure, exfiltrating sensitive credentials, and deploying persistent backdoors.
Likely Case
Attackers bypass authentication to access the ClearPass administrative interface, modify policies, extract user credentials, and potentially pivot to other network resources.
If Mitigated
With proper network segmentation and access controls, impact is limited to the ClearPass system itself, though credential exposure remains a significant risk.
🎯 Exploit Status
The vulnerability allows remote exploitation without authentication, suggesting relatively simple exploitation methods.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 6.8.9-HF1, 6.9.7-HF1, or 6.10.2 depending on current version
Vendor Advisory: https://www.arubanetworks.com/assets/alert/ARUBA-PSA-2021-018.txt
Restart Required: Yes
Instructions:
1. Download the appropriate patch from the Aruba support portal. 2. Backup current configuration. 3. Apply the patch following Aruba's documented procedures. 4. Restart the ClearPass services or appliance as required.
🔧 Temporary Workarounds
Network Access Restriction
allRestrict network access to ClearPass Policy Manager to only trusted administrative networks
Firewall Rules
allImplement strict firewall rules to limit access to ClearPass management interfaces
🧯 If You Can't Patch
- Isolate ClearPass system from internet and restrict internal access to only necessary administrative networks
- Implement additional authentication layers (MFA) for administrative access and monitor for suspicious authentication attempts
🔍 How to Verify
Check if Vulnerable:
Check ClearPass version via web interface (Admin > Support > About) or CLI command 'appliance version'Check Version:
appliance versionVerify Fix Applied:
Verify version is 6.8.9-HF1 or higher, 6.9.7-HF1 or higher, or 6.10.2 or higher📡 Detection & Monitoring
Log Indicators:
- Unusual authentication patterns
- Administrative access from unexpected IP addresses
- Failed authentication attempts followed by successful access
Network Indicators:
- Unusual traffic patterns to ClearPass management interfaces
- Authentication bypass attempts
SIEM Query:
source="clearpass" AND (event_type="authentication" AND result="success" AND source_ip NOT IN [admin_ips])