CVE-2022-23971
📋 TL;DR
This vulnerability allows unauthenticated attackers on the local network to perform path traversal attacks on ASUS RT-AX56U routers. By exploiting insufficient URL parameter filtering, attackers can overwrite system files with specially crafted PLC/PORT files, causing service disruption. Only ASUS RT-AX56U router users are affected.
💻 Affected Systems
- ASUS RT-AX56U
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete router compromise leading to persistent backdoor installation, network traffic interception, and bricking of the device requiring hardware replacement.
Likely Case
Service disruption through file overwrites causing router instability, temporary network outages, and potential configuration loss.
If Mitigated
Limited to internal network attacks only; external attackers cannot exploit this without first gaining LAN access.
🎯 Exploit Status
Exploitation is straightforward for attackers with LAN access; no authentication required.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Firmware version 3.0.0.4.386.46061 or later
Vendor Advisory: https://www.asus.com/Networking-IoT-Servers/WiFi-Routers/ASUS-WiFi-Routers/RT-AX56U/HelpDesk_BIOS/
Restart Required: Yes
Instructions:
1. Log into router admin interface. 2. Navigate to Administration > Firmware Upgrade. 3. Download latest firmware from ASUS support site. 4. Upload and install firmware. 5. Reboot router after installation.
🔧 Temporary Workarounds
Disable PLC/PORT file upload feature
allDisable the vulnerable file upload functionality if not required
Network segmentation
allIsolate router management interface to trusted VLAN only
🧯 If You Can't Patch
- Physically isolate router from untrusted devices on LAN
- Implement strict network access controls to limit who can access router management
🔍 How to Verify
Check if Vulnerable:
Check current firmware version in router admin interface under Administration > Firmware UpgradeCheck Version:
curl -s http://router.asus.com/Advanced_FirmwareUpgrade_Content.asp | grep 'Firmware Version'Verify Fix Applied:
Verify firmware version is 3.0.0.4.386.46061 or higher after update📡 Detection & Monitoring
Log Indicators:
- Multiple failed PLC/PORT file upload attempts
- Unusual file modification timestamps in system directories
Network Indicators:
- Unusual HTTP POST requests to update_PLC/PORT endpoints from LAN devices
SIEM Query:
source="router.log" AND ("update_PLC" OR "update_PORT") AND status=200