CVE-2023-25092
📋 TL;DR
This CVE describes multiple buffer overflow vulnerabilities in the vtysh_ubus binary of Milesight UR32L routers, caused by unsafe sprintf usage. Attackers with high privileges can send specially crafted HTTP requests to trigger arbitrary code execution. Only Milesight UR32L router users running vulnerable firmware are affected.
💻 Affected Systems
- Milesight UR32L
📦 What is this software?
Ur32l Firmware by Milesight
⚠️ Risk & Real-World Impact
Worst Case
Complete device compromise allowing attacker to execute arbitrary code, pivot to internal networks, and maintain persistent access.
Likely Case
Privileged attacker gains remote code execution on the router, potentially intercepting traffic or modifying configurations.
If Mitigated
With proper network segmentation and access controls, impact limited to the router itself without lateral movement.
🎯 Exploit Status
Exploitation requires authenticated access and knowledge of buffer overflow techniques.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: Not publicly available
Restart Required: Yes
Instructions:
1. Check Milesight website for firmware updates
2. Download latest firmware
3. Upload via web interface
4. Apply and reboot router
🔧 Temporary Workarounds
Restrict HTTP Management Access
linuxLimit HTTP management 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 80 -j DROP
Disable Unused Features
linuxDisable HTTP management interface if not required
service httpd stop
chkconfig httpd off
🧯 If You Can't Patch
- Segment router on isolated network VLAN
- Implement strict access controls limiting admin privileges
🔍 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 newer than v32.3.0.5📡 Detection & Monitoring
Log Indicators:
- Unusual HTTP requests to management interface
- Multiple failed authentication attempts followed by buffer overflow patterns
Network Indicators:
- HTTP requests with unusually long interface or out_acl parameters
- Traffic patterns suggesting buffer overflow exploitation
SIEM Query:
source="router_logs" AND (http_uri="*interface=*" OR http_uri="*out_acl=*") AND http_uri_length>100