CVE-2021-45039
📋 TL;DR
This critical vulnerability allows remote unauthenticated attackers to execute arbitrary code on Uniview IP cameras by exploiting a buffer overflow in an undocumented UDP service on port 7788. Successful exploitation enables attackers to start telnetd with hardcoded credentials and bypass restricted shell access. Organizations using affected Uniview IP camera models are at risk.
💻 Affected Systems
- Uniview IP Camera models: IPC_G6103
- IPC_G61
- IPC21
- IPC23
- IPC32
- IPC36
- IPC62
- IPC_HCMN
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of camera systems leading to persistent backdoor access, lateral movement to internal networks, video surveillance disruption, and potential use in botnets or ransomware attacks.
Likely Case
Remote code execution leading to camera compromise, unauthorized access to video feeds, and potential use as foothold for further network attacks.
If Mitigated
Limited impact if cameras are isolated in separate network segments with strict firewall rules blocking port 7788.
🎯 Exploit Status
Exploit chain is well-documented: buffer overflow → start telnetd → use hardcoded credentials root/123456 → bypass restricted shell via ECHO command.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check vendor advisory for specific patched firmware versions
Vendor Advisory: https://www.uniview.com/About_Us/Security/Notice/202112/920471_140493_0.htm
Restart Required: Yes
Instructions:
1. Check current firmware version. 2. Download latest firmware from Uniview support portal. 3. Upload firmware to camera via web interface. 4. Reboot camera after update completes.
🔧 Temporary Workarounds
Network Segmentation and Firewall Rules
linuxBlock UDP port 7788 at network perimeter and segment cameras from critical networks
iptables -A INPUT -p udp --dport 7788 -j DROP
iptables -A FORWARD -p udp --dport 7788 -j DROP
Disable Telnet Service
linuxRemove or disable telnetd service if camera configuration allows
chmod -x /usr/sbin/telnetd
rm /usr/sbin/telnetd
🧯 If You Can't Patch
- Immediately block UDP port 7788 at network firewalls and ensure cameras are in isolated VLANs
- Change default credentials and monitor for unauthorized telnet connections
🔍 How to Verify
Check if Vulnerable:
Use nmap to scan for open UDP port 7788: nmap -sU -p 7788 <camera_ip>Check Version:
Check camera web interface under System Information or use curl to query status pageVerify Fix Applied:
Verify port 7788 is no longer responding and check firmware version matches patched release📡 Detection & Monitoring
Log Indicators:
- Unexpected telnetd service startup
- Failed authentication attempts with root/123456
- Unusual UDP traffic on port 7788
Network Indicators:
- UDP traffic to port 7788 from unexpected sources
- Telnet connections to camera ports
- Unusual outbound traffic from cameras
SIEM Query:
source_port=7788 OR dest_port=7788 OR (service=telnet AND (username=root AND password=123456))