CVE-2020-29490
📋 TL;DR
This vulnerability allows a remote authenticated attacker to cause a Denial of Service (Storage Processor Panic) on Dell EMC Unity storage systems by sending specially crafted UDP requests to NFS exports. It affects Dell EMC Unity, Unity XT, and UnityVSA storage systems. The attack requires authentication but can lead to complete service disruption.
💻 Affected Systems
- Dell EMC Unity
- Dell EMC Unity XT
- Dell EMC UnityVSA
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete storage system outage with Storage Processor Panic, disrupting all storage services and potentially causing data unavailability until manual recovery.
Likely Case
Temporary service disruption affecting NFS exports, requiring system reboot and causing downtime for dependent applications.
If Mitigated
Limited impact with proper network segmentation and access controls preventing unauthorized access to NFS services.
🎯 Exploit Status
Exploitation requires valid authentication credentials and network access to NFS services. UDP-based attack makes it relatively simple to execute once authenticated.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 5.0.4.0.5.012 or later
Vendor Advisory: https://www.dell.com/support/kbdoc/000181248
Restart Required: Yes
Instructions:
1. Download the appropriate firmware update from Dell Support. 2. Follow Dell's firmware update procedures for Unity/Unity XT/UnityVSA systems. 3. Apply the update to all affected storage processors. 4. Reboot the storage system as required by the update process.
🔧 Temporary Workarounds
Disable NFS Exports
allTemporarily disable NFS exports on vulnerable systems if they are not required for operations.
Unity CLI: uemcli -u admin -p <password> /net/nas/server -id <server_id> set -nfsEnabled no
Restrict NFS Access
allImplement strict network access controls to limit which hosts can connect to NFS services.
Unity CLI: uemcli -u admin -p <password> /net/nas/nfsExport -id <export_id> set -hosts <allowed_hosts>
🧯 If You Can't Patch
- Implement strict network segmentation to isolate NFS services from untrusted networks
- Enforce strong authentication policies and regularly rotate credentials for NFS access
🔍 How to Verify
Check if Vulnerable:
Check system version via Unity Unisphere GUI or CLI: uemcli /sys/general showCheck Version:
uemcli /sys/general show | grep 'Version'Verify Fix Applied:
Verify system version is 5.0.4.0.5.012 or later and test NFS functionality remains operational📡 Detection & Monitoring
Log Indicators:
- Storage processor panic events in system logs
- Unexpected NFS service restarts
- Multiple failed authentication attempts followed by UDP flood to NFS ports
Network Indicators:
- Unusual UDP traffic patterns to NFS ports (2049)
- Multiple malformed NFS requests from single source
SIEM Query:
source="unity_logs" AND ("panic" OR "processor reset" OR "nfs crash")