CVE-2025-44651
📋 TL;DR
This vulnerability in TRENDnet TPL-430AP access points allows denial-of-service attacks when the USERLIMIT_GLOBAL option is set to 0 in bftpd configuration, enabling unlimited user connections that can exhaust system resources. It affects organizations using TRENDnet TPL-430AP access points with firmware version 1.0.
💻 Affected Systems
- TRENDnet TPL-430AP
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete service disruption of the access point, making wireless networks unavailable for all connected users and devices.
Likely Case
Intermittent service degradation or temporary unavailability of the wireless network as connection limits are exhausted.
If Mitigated
Minimal impact with proper connection limiting and monitoring in place.
🎯 Exploit Status
Exploitation requires only establishing multiple connections to exhaust resources, no authentication needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: http://trendnet.com
Restart Required: Yes
Instructions:
1. Check TRENDnet website for firmware updates. 2. Download latest firmware. 3. Upload to device via web interface. 4. Apply update and restart device.
🔧 Temporary Workarounds
Configure Connection Limits
linuxManually set USERLIMIT_GLOBAL to a reasonable value in bftpd configuration to prevent unlimited connections.
Edit bftpd configuration file and set USERLIMIT_GLOBAL=50 (or appropriate limit)
Disable Unused Services
linuxDisable bftpd service if not required for device functionality.
Find and stop bftpd service: systemctl stop bftpd
Disable from startup: systemctl disable bftpd
🧯 If You Can't Patch
- Implement network segmentation to isolate vulnerable devices from untrusted networks.
- Deploy rate limiting or connection throttling at network perimeter to prevent connection exhaustion attacks.
🔍 How to Verify
Check if Vulnerable:
Check bftpd configuration file for USERLIMIT_GLOBAL=0 setting. Use command: grep USERLIMIT_GLOBAL /etc/bftpd.confCheck Version:
Check web interface or use command: cat /etc/versionVerify Fix Applied:
Verify USERLIMIT_GLOBAL is set to a non-zero value in configuration and bftpd service respects the limit.📡 Detection & Monitoring
Log Indicators:
- High number of connection attempts in bftpd logs
- Connection limit warnings or errors
- Unusual spike in authentication attempts
Network Indicators:
- Abnormal number of connections to port 21 (FTP)
- Multiple connection attempts from single IPs
- Network performance degradation
SIEM Query:
source="bftpd" AND ("connection limit" OR "max connections" OR "USERLIMIT")