CVE-2025-50399
📋 TL;DR
This vulnerability allows remote attackers to execute arbitrary code on FAST FAC1200R F400_FAC1200R_Q devices by exploiting a buffer overflow in the password parameter. Attackers can gain full control of affected devices, potentially compromising entire networks. This affects all users of vulnerable FAST FAC1200R devices.
💻 Affected Systems
- FAST FAC1200R F400_FAC1200R_Q
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete device takeover leading to persistent backdoor installation, network pivoting to other systems, and data exfiltration.
Likely Case
Remote code execution allowing device compromise, credential theft, and use as attack platform.
If Mitigated
Limited impact if devices are isolated in separate VLANs with strict network segmentation.
🎯 Exploit Status
Buffer overflow vulnerabilities with public PoC are often quickly weaponized. CWE-120 indicates classic buffer copy without checking size.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not available
Restart Required: Yes
Instructions:
1. Contact FAST vendor for security advisory 2. Apply firmware update when available 3. Reboot device after update
🔧 Temporary Workarounds
Network Segmentation
allIsolate affected devices in separate VLAN with strict firewall rules
Access Control
linuxRestrict web interface access to trusted IP addresses only
iptables -A INPUT -p tcp --dport 80 -s trusted_ip -j ACCEPT
iptables -A INPUT -p tcp --dport 443 -s trusted_ip -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
iptables -A INPUT -p tcp --dport 443 -j DROP
🧯 If You Can't Patch
- Disable remote management interfaces if not required
- Implement strict network monitoring for unusual traffic patterns
🔍 How to Verify
Check if Vulnerable:
Check device firmware version and compare with vendor's patched version listCheck Version:
Check web interface admin panel or use vendor-specific CLI commandsVerify Fix Applied:
Verify firmware version matches vendor's patched version and test password parameter with overflow payloads📡 Detection & Monitoring
Log Indicators:
- Unusual authentication attempts
- Large password parameter values in web logs
- Process crashes or restarts
Network Indicators:
- Unusual outbound connections from device
- Exploit kit traffic patterns
- Shellcode detection in network traffic
SIEM Query:
source="device_logs" AND (password.length>100 OR "buffer overflow" OR "segmentation fault")