CVE-2021-21503
📋 TL;DR
CVE-2021-21503 is an improper input sanitization vulnerability in PowerScale OneFS that allows authenticated Compadmin users to execute arbitrary commands with elevated privileges. This affects PowerScale OneFS versions 8.1.2, 8.2.2, and 9.1.0. Successful exploitation could lead to complete system compromise.
💻 Affected Systems
- Dell EMC PowerScale OneFS
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Compadmin user gains root privileges, leading to complete system compromise, data exfiltration, or ransomware deployment.
Likely Case
Compadmin user escalates to root privileges, enabling unauthorized access to sensitive data and system configuration changes.
If Mitigated
With proper access controls and monitoring, exploitation would be detected and contained before significant damage occurs.
🎯 Exploit Status
Exploitation requires Compadmin credentials. No public exploit code has been disclosed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Update to OneFS 8.1.3, 8.2.3, or 9.1.1 or later.
Vendor Advisory: https://www.dell.com/support/kbdoc/000183717
Restart Required: Yes
Instructions:
1. Review Dell advisory 000183717. 2. Backup system configuration and data. 3. Apply the appropriate OneFS update via the OneFS web administration interface or CLI. 4. Reboot the cluster as required by the update process.
🔧 Temporary Workarounds
Restrict Compadmin Access
allLimit Compadmin user accounts to only trusted personnel and monitor their activity.
Implement Least Privilege
allReview and remove unnecessary Compadmin privileges where possible.
🧯 If You Can't Patch
- Implement strict access controls for Compadmin accounts and monitor all Compadmin command execution.
- Segment network to isolate PowerScale systems and restrict access to management interfaces.
🔍 How to Verify
Check if Vulnerable:
Check OneFS version via CLI: 'isi version' or web interface. If version is 8.1.2, 8.2.2, or 9.1.0, system is vulnerable.Check Version:
isi versionVerify Fix Applied:
After patching, verify version is 8.1.3, 8.2.3, 9.1.1 or later using 'isi version' command.📡 Detection & Monitoring
Log Indicators:
- Unusual command execution by Compadmin users, especially privilege escalation attempts.
- Audit logs showing Compadmin users executing commands with unexpected parameters.
Network Indicators:
- Unusual outbound connections from PowerScale management interfaces.
SIEM Query:
source="powerscale" AND user="compadmin" AND (event="command_execution" OR event="privilege_escalation")