CVE-2020-6871
📋 TL;DR
This CVE describes an authentication bypass vulnerability in ZTE server management software that allows attackers to skip authentication and execute privileged commands. It affects multiple ZTE server models running specific vulnerable firmware versions. The high CVSS score of 9.8 indicates critical severity.
💻 Affected Systems
- ZTE R5300G4
- ZTE R8500G4
- ZTE R5500G4
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise allowing attackers to execute arbitrary commands with administrative privileges, potentially leading to data theft, system destruction, or lateral movement within the network.
Likely Case
Unauthorized access to server management functions, privilege escalation, and execution of administrative commands without proper authentication.
If Mitigated
Limited impact if systems are isolated, have network segmentation, and additional authentication layers are in place.
🎯 Exploit Status
The vulnerability allows skipping authentication entirely, making exploitation straightforward if the attack vector is accessible.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check ZTE advisory for specific patched versions
Vendor Advisory: http://support.zte.com.cn/support/news/LoopholeInfoDetail.aspx?newsId=1013203
Restart Required: Yes
Instructions:
1. Access ZTE support portal for affected firmware versions. 2. Download and apply the latest firmware update. 3. Restart the server management module or entire system as required. 4. Verify the update was successful.
🔧 Temporary Workarounds
Network Isolation
linuxRestrict access to server management interfaces to trusted networks only
iptables -A INPUT -p tcp --dport [management-port] -s [trusted-network] -j ACCEPT
iptables -A INPUT -p tcp --dport [management-port] -j DROP
Access Control Lists
allImplement strict network ACLs to limit access to management interfaces
🧯 If You Can't Patch
- Isolate affected systems in a separate VLAN with strict access controls
- Implement additional authentication layers (2FA, VPN, jump hosts) before accessing management interfaces
🔍 How to Verify
Check if Vulnerable:
Check firmware version via management interface or CLI: show version or equivalent commandCheck Version:
show version (or equivalent vendor-specific command)Verify Fix Applied:
Verify firmware version has been updated to a version not listed in the affected versions📡 Detection & Monitoring
Log Indicators:
- Unauthenticated access attempts to management interface
- Privileged commands executed without prior authentication logs
- Access from unexpected IP addresses to management ports
Network Indicators:
- Traffic to server management ports (typically 80, 443, or custom ports) from unauthorized sources
- Unusual command sequences sent to management interface
SIEM Query:
source_ip NOT IN (trusted_ips) AND dest_port IN (management_ports) AND auth_result="success"