CVE-2021-36294
📋 TL;DR
CVE-2021-36294 is an authentication bypass vulnerability in Dell VNX2 OE for File versions 8.1.21.266 and earlier. A remote attacker can forge a cookie to log in as any user without credentials. This affects organizations using vulnerable Dell VNX2 storage systems.
💻 Affected Systems
- Dell VNX2 OE for File
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise allowing attacker to access, modify, or delete all stored data, disrupt storage operations, and potentially pivot to other network systems.
Likely Case
Unauthorized access to sensitive files and storage management functions, data theft, and potential ransomware deployment.
If Mitigated
Limited impact if systems are isolated, monitored, and have additional authentication layers, though risk remains significant.
🎯 Exploit Status
Exploitation requires cookie forgery but is straightforward once understood; no public exploit code is widely known.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Update to version later than 8.1.21.266; refer to Dell advisory for specific patched versions.
Vendor Advisory: https://www.dell.com/support/kbdoc/en-us/000191155/dsa-2021-164-dell-vnx2-control-station-security-update-for-multiple-vulnerabilities
Restart Required: Yes
Instructions:
1. Review Dell advisory DSA-2021-164. 2. Download and apply the security update from Dell support. 3. Restart the VNX2 system as required. 4. Verify the update is applied successfully.
🔧 Temporary Workarounds
Network Isolation
allRestrict network access to VNX2 systems to only trusted IPs and networks.
Use firewall rules to block all inbound traffic except from management networks.
Enhanced Monitoring
allMonitor authentication logs for unusual login attempts or cookie anomalies.
Configure syslog or SIEM to alert on failed or suspicious authentication events.
🧯 If You Can't Patch
- Isolate the VNX2 system from untrusted networks and the internet immediately.
- Implement strict access controls and monitor all authentication attempts closely for signs of exploitation.
🔍 How to Verify
Check if Vulnerable:
Check the VNX2 OE version via the management interface; if version is 8.1.21.266 or earlier, it is vulnerable.Check Version:
Use the VNX2 management GUI or CLI to check the software version; specific commands vary by setup.Verify Fix Applied:
After patching, confirm the version is updated to a patched release (e.g., 8.1.21.267 or later) and test authentication controls.📡 Detection & Monitoring
Log Indicators:
- Unusual login attempts, especially from unexpected IPs or with forged cookies.
- Authentication logs showing successful logins without proper credential validation.
Network Indicators:
- Suspicious HTTP requests to VNX2 management interfaces involving cookie manipulation.
- Traffic patterns indicating unauthorized access attempts.
SIEM Query:
Example: 'source="vnx2_logs" AND (event_type="authentication" AND result="success") AND src_ip NOT IN trusted_ips'