CVE-2024-35279
📋 TL;DR
A stack-based buffer overflow vulnerability in Fortinet FortiOS allows remote unauthenticated attackers to execute arbitrary code via crafted UDP packets through CAPWAP control. This affects FortiOS versions 7.2.4-7.2.8 and 7.4.0-7.4.4 when the fabric service is running on exposed interfaces. Attackers must bypass FortiOS stack protections to exploit this vulnerability.
💻 Affected Systems
- Fortinet FortiOS
📦 What is this software?
Fortios by Fortinet
Fortios by Fortinet
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise with remote code execution leading to data theft, lateral movement, and persistent backdoor installation.
Likely Case
Service disruption, denial of service, or limited code execution if stack protections are partially effective.
If Mitigated
No impact if fabric service is disabled on exposed interfaces or proper network segmentation is implemented.
🎯 Exploit Status
Exploitation requires bypassing FortiOS stack protections and fabric service must be running on exposed interface
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 7.2.9 and 7.4.5
Vendor Advisory: https://fortiguard.fortinet.com/psirt/FG-IR-24-160
Restart Required: No
Instructions:
1. Log into FortiGate admin interface. 2. Navigate to System > Firmware. 3. Upload and install FortiOS version 7.2.9 or 7.4.5. 4. Verify successful upgrade.
🔧 Temporary Workarounds
Disable fabric service on exposed interfaces
allPrevent exploitation by disabling the fabric service on internet-facing or untrusted network interfaces
config system interface
edit <interface_name>
set fabric-service disable
end
Implement network segmentation
allRestrict UDP CAPWAP traffic to trusted networks only using firewall policies
config firewall policy
edit 0
set srcintf <trusted_interface>
set dstintf <internal_interface>
set srcaddr all
set dstaddr all
set service CAPWAP
set action accept
end
🧯 If You Can't Patch
- Disable fabric service on all exposed interfaces immediately
- Implement strict firewall rules to block UDP CAPWAP traffic from untrusted networks
🔍 How to Verify
Check if Vulnerable:
Check FortiOS version with 'get system status' and verify if between 7.2.4-7.2.8 or 7.4.0-7.4.4Check Version:
get system status | grep VersionVerify Fix Applied:
Verify FortiOS version is 7.2.9 or higher for 7.2.x branch, or 7.4.5 or higher for 7.4.x branch📡 Detection & Monitoring
Log Indicators:
- Unexpected CAPWAP protocol errors
- Fabric service crashes
- Memory access violation logs
- Unusual UDP traffic on CAPWAP ports
Network Indicators:
- Malformed UDP packets to CAPWAP ports (5246, 5247)
- Unusual traffic patterns to fabric service ports
- CAPWAP protocol anomalies
SIEM Query:
source="fortigate" AND (event_type="anomaly" OR event_type="attack" OR event_type="system") AND (message="*CAPWAP*" OR message="*fabric*" OR message="*buffer*" OR message="*overflow*")