CVE-2024-46666
📋 TL;DR
This CVE describes a resource allocation vulnerability in FortiOS that allows remote unauthenticated attackers to send specially crafted requests to specific endpoints, causing denial of service by preventing access to the GUI. Affected systems include FortiOS versions 7.6.0, 7.4.0 through 7.4.4, and all versions of 7.2, 7.0, and 6.4.
💻 Affected Systems
- FortiOS
📦 What is this software?
Fortios by Fortinet
Fortios by Fortinet
Fortios by Fortinet
⚠️ Risk & Real-World Impact
Worst Case
Complete denial of service preventing administrative access to FortiOS GUI, requiring physical console access or reboot to restore functionality.
Likely Case
Temporary GUI unavailability requiring administrator intervention to restore access.
If Mitigated
Minimal impact with proper network segmentation and request filtering in place.
🎯 Exploit Status
Exploitation requires knowledge of specific vulnerable endpoints but does not require authentication.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 7.6.1, 7.4.5, and later versions for affected branches
Vendor Advisory: https://fortiguard.fortinet.com/psirt/FG-IR-24-250
Restart Required: Yes
Instructions:
1. Backup current configuration. 2. Download appropriate firmware version from Fortinet support portal. 3. Upload firmware to FortiGate device. 4. Install firmware update. 5. Reboot device. 6. Verify version and functionality.
🔧 Temporary Workarounds
Restrict GUI Access
allLimit access to FortiOS GUI to trusted IP addresses only
config system interface
edit <interface_name>
set allowaccess https
set source-ip <trusted_ip_range>
end
Disable GUI on External Interfaces
allRemove HTTPS/HTTP access from internet-facing interfaces
config system interface
edit <external_interface>
unset allowaccess https
unset allowaccess http
end
🧯 If You Can't Patch
- Implement strict network ACLs to limit access to FortiOS GUI endpoints
- Deploy WAF or IPS with rate limiting rules for FortiOS management traffic
🔍 How to Verify
Check if Vulnerable:
Check FortiOS version via CLI: get system status | grep VersionCheck Version:
get system status | grep VersionVerify Fix Applied:
Verify version is 7.6.1, 7.4.5, or later patched version📡 Detection & Monitoring
Log Indicators:
- Multiple failed GUI login attempts
- Unusual request patterns to GUI endpoints
- High resource utilization alerts
Network Indicators:
- Unusual volume of requests to /login or other GUI endpoints
- Requests from unexpected source IPs to management interface
SIEM Query:
source="fortigate" AND (url="*/login*" OR url="*/gui*" OR url="*/api*" ) AND status=200 | stats count by src_ip