CVE-2023-25104
📋 TL;DR
This vulnerability allows authenticated attackers to execute arbitrary code on Milesight UR32L routers by sending specially crafted HTTP requests that trigger buffer overflows in the vtysh_ubus binary. The vulnerability affects systems running vulnerable firmware versions and requires attacker privileges to exploit.
💻 Affected Systems
- Milesight UR32L
📦 What is this software?
Ur32l Firmware by Milesight
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attackers to install persistent backdoors, pivot to internal networks, or use the device as part of a botnet.
Likely Case
Local privilege escalation leading to full control of the router, enabling traffic interception, configuration changes, and lateral movement.
If Mitigated
Limited impact if proper network segmentation and access controls prevent unauthorized users from reaching the vulnerable service.
🎯 Exploit Status
Exploitation requires authenticated access to the HTTP interface and knowledge of the vulnerable function parameters.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: Not available
Restart Required: No
Instructions:
1. Monitor Milesight security advisories for patch availability
2. Apply firmware updates when released
3. Verify patch installation by checking firmware version
🔧 Temporary Workarounds
Network Segmentation
linuxRestrict access to the router's management interface to trusted networks only
iptables -A INPUT -p tcp --dport 80 -s TRUSTED_NETWORK -j ACCEPT
iptables -A INPUT -p tcp --dport 80 -j DROP
Disable Vulnerable Service
linuxDisable the vtysh_ubus service if not required for operation
killall vtysh_ubus
chmod -x /path/to/vtysh_ubus
🧯 If You Can't Patch
- Implement strict network access controls to limit who can reach the router's management interface
- Monitor for unusual HTTP requests to the router's web interface and investigate any anomalies
🔍 How to Verify
Check if Vulnerable:
Check firmware version via web interface or SSH: cat /etc/versionCheck Version:
cat /etc/versionVerify Fix Applied:
Verify firmware version is updated beyond v32.3.0.5 when patch becomes available📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP POST requests to router management interface
- Multiple failed authentication attempts followed by successful login
Network Indicators:
- HTTP traffic to router management interface from unexpected sources
- Unusual outbound connections from the router
SIEM Query:
source="router_logs" AND (http_method="POST" AND uri="/cgi-bin/luci" AND (user_agent CONTAINS "curl" OR user_agent CONTAINS "python"))