CVE-2022-22278
📋 TL;DR
This vulnerability in SonicWall SonicOS CFS allows attackers to cause HTTP Denial of Service (DoS) by triggering large 403 forbidden responses when accessing prohibited resources. Attackers can exploit this to exhaust system resources and disrupt legitimate traffic. Organizations using affected SonicWall firewall products with CFS enabled are vulnerable.
💻 Affected Systems
- SonicWall SonicOS
📦 What is this software?
Nsv 10 Firmware by Sonicwall
Nsv 25 Firmware by Sonicwall
Nsv 50 Firmware by Sonicwall
Tz300p Firmware by Sonicwall
Tz300w Firmware by Sonicwall
Tz350 Firmware by Sonicwall
Tz350w Firmware by Sonicwall
Tz370 Firmware by Sonicwall
Tz370w Firmware by Sonicwall
Tz400 Firmware by Sonicwall
Tz400w Firmware by Sonicwall
Tz470 Firmware by Sonicwall
Tz470w Firmware by Sonicwall
Tz500 Firmware by Sonicwall
Tz500w Firmware by Sonicwall
Tz570 Firmware by Sonicwall
Tz570p Firmware by Sonicwall
Tz570w Firmware by Sonicwall
Tz600 Firmware by Sonicwall
Tz600p Firmware by Sonicwall
Tz670 Firmware by Sonicwall
⚠️ Risk & Real-World Impact
Worst Case
Complete disruption of HTTP services through resource exhaustion, potentially causing extended downtime for web applications and services behind the firewall.
Likely Case
Degraded HTTP performance and intermittent service disruptions affecting users accessing web resources through the firewall.
If Mitigated
Minimal impact with proper rate limiting, monitoring, and timely patching in place.
🎯 Exploit Status
Exploitation requires sending HTTP requests to trigger 403 responses, which is straightforward. No authentication needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: SonicOS 7.0.1-5051 and later
Vendor Advisory: https://psirt.global.sonicwall.com/vuln-detail/SNWLID-2022-0004
Restart Required: Yes
Instructions:
1. Log into SonicWall management interface. 2. Navigate to System > Settings > Firmware & Backups. 3. Download and install SonicOS 7.0.1-5051 or later. 4. Reboot the firewall after installation completes.
🔧 Temporary Workarounds
Disable Content Filtering Service
allTemporarily disable CFS to prevent exploitation while awaiting patch
Navigate to Security Services > Content Filter > General and disable 'Enable Content Filter Service'
Implement Rate Limiting
allConfigure rate limiting on HTTP traffic to mitigate DoS impact
Configure Security Services > App Control > Settings with appropriate rate limits
🧯 If You Can't Patch
- Implement network-level rate limiting using upstream devices
- Monitor for abnormal 403 response patterns and block offending IPs
🔍 How to Verify
Check if Vulnerable:
Check SonicOS version in System > Status > System Information. If version is 7.0.1-5050 or earlier and CFS is enabled, system is vulnerable.Check Version:
show version (from CLI) or check System > Status > System Information in web interfaceVerify Fix Applied:
Verify SonicOS version is 7.0.1-5051 or later in System > Status > System Information.📡 Detection & Monitoring
Log Indicators:
- Unusually high volume of 403 HTTP responses
- Large response size entries in firewall logs
- Resource exhaustion alerts
Network Indicators:
- Spike in HTTP traffic to firewall
- Abnormal pattern of requests to trigger 403 responses
SIEM Query:
source="sonicwall" (response_code="403" AND response_size>threshold) | stats count by src_ip