CVE-2021-3053
📋 TL;DR
An unauthenticated attacker can send specially crafted network traffic through Palo Alto Networks PAN-OS firewalls to crash the dataplane service. Repeated exploitation causes the device to restart into maintenance mode, creating a denial-of-service condition. This affects PAN-OS 8.1, 9.0, 9.1, and 10.0 versions before specific patch releases.
💻 Affected Systems
- Palo Alto Networks PAN-OS
📦 What is this software?
Pan Os by Paloaltonetworks
Pan Os by Paloaltonetworks
Pan Os by Paloaltonetworks
Pan Os by Paloaltonetworks
⚠️ Risk & Real-World Impact
Worst Case
Complete denial of service with firewall entering maintenance mode, requiring manual intervention to restore functionality, potentially disrupting all network traffic.
Likely Case
Service disruption causing firewall to restart and enter maintenance mode, requiring administrative action to restore normal operations.
If Mitigated
No impact if patched or if traffic filtering prevents crafted packets from reaching the firewall.
🎯 Exploit Status
Exploitation requires sending specifically crafted network traffic through the firewall, but no authentication is needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: PAN-OS 8.1.20, 9.0.14, 9.1.9, or 10.0.5
Vendor Advisory: https://security.paloaltonetworks.com/CVE-2021-3053
Restart Required: Yes
Instructions:
1. Download appropriate PAN-OS patch version from Palo Alto support portal. 2. Upload to firewall management interface. 3. Install patch via System > Software > Install. 4. Commit configuration changes. 5. Reboot firewall to complete installation.
🔧 Temporary Workarounds
Traffic Filtering
allImplement network controls to filter or block suspicious traffic patterns that could trigger the vulnerability.
Network Segmentation
allRestrict access to firewall interfaces to trusted networks only.
🧯 If You Can't Patch
- Implement strict network access controls to limit which systems can send traffic to firewall interfaces.
- Deploy intrusion prevention systems or network monitoring to detect and block exploitation attempts.
🔍 How to Verify
Check if Vulnerable:
Check PAN-OS version via WebUI (Dashboard > System Information) or CLI (show system info). Compare against affected version ranges.Check Version:
show system info | match versionVerify Fix Applied:
Verify PAN-OS version is 8.1.20+, 9.0.14+, 9.1.9+, or 10.0.5+ and monitor for dataplane crashes or maintenance mode events.📡 Detection & Monitoring
Log Indicators:
- Dataplane crash logs
- Firewall entering maintenance mode
- Unexpected device restarts
Network Indicators:
- Unusual traffic patterns to firewall interfaces
- Repeated connection attempts with malformed packets
SIEM Query:
source="pan-firewall" (event_type="dataplane_crash" OR event_type="maintenance_mode")