CVE-2023-25114
📋 TL;DR
This vulnerability allows authenticated attackers with high privileges to execute arbitrary code on Milesight UR32L routers by sending specially crafted HTTP requests. The buffer overflow occurs in the vtysh_ubus binary when processing OpenVPN client configuration. Affected users are those running vulnerable versions of the UR32L router firmware.
💻 Affected Systems
- Milesight UR32L
📦 What is this software?
Ur32l Firmware by Milesight
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attacker to install persistent backdoors, pivot to internal networks, or use the device as part of a botnet.
Likely Case
Attacker gains full control of the router, enabling traffic interception, credential theft, and lateral movement to connected systems.
If Mitigated
Limited impact due to network segmentation and restricted administrative access, though device integrity may still be compromised.
🎯 Exploit Status
Exploitation requires administrative access and knowledge of the vulnerable function's memory layout.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: Not available
Restart Required: No
Instructions:
No official patch available. Monitor Milesight security advisories for updates.
🔧 Temporary Workarounds
Disable OpenVPN client functionality
allRemove or disable OpenVPN client configuration to prevent exploitation of the vulnerable set_openvpn_client function
Access router web interface > VPN > OpenVPN > Disable client functionality
Restrict administrative access
allLimit administrative interface access to trusted IP addresses only
Configure firewall rules to restrict access to router management interface (typically port 80/443)
🧯 If You Can't Patch
- Segment UR32L routers on isolated network segments to limit lateral movement
- Implement strict monitoring for unusual HTTP requests to the administrative interface
🔍 How to Verify
Check if Vulnerable:
Check firmware version via web interface: System > Status > Firmware VersionCheck Version:
Not applicable via command line without shell accessVerify Fix Applied:
Verify firmware version is newer than v32.3.0.5 when patch becomes available📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP POST requests to OpenVPN configuration endpoints
- Multiple failed authentication attempts followed by successful login
Network Indicators:
- HTTP traffic to router administrative interface with unusually long parameter values
- Outbound connections from router to unexpected destinations
SIEM Query:
source_ip="router_ip" AND (http_method="POST" AND uri CONTAINS "openvpn" AND param_length>1000)