CVE-2021-28813
📋 TL;DR
This vulnerability allows remote attackers to read sensitive information stored insecurely on affected QNAP switches. Attackers can exploit this by accessing an unrestricted storage mechanism without authentication. Affected systems include QSW-M2116P-2T2S and QNAP switches running specific versions of QuNetSwitch.
💻 Affected Systems
- QSW-M2116P-2T2S
- QGD-1600P
- QGD-1602P
- QGD-3014PT
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote attackers gain unauthorized access to sensitive configuration data, credentials, or other critical information, potentially leading to full network compromise.
Likely Case
Attackers extract sensitive switch configuration data, which could be used for further attacks or network reconnaissance.
If Mitigated
With proper network segmentation and access controls, impact is limited to information disclosure without direct system compromise.
🎯 Exploit Status
Exploitation requires network access to the switch but no authentication, making it relatively simple for attackers.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: QSW-M2116P-2T2S: 1.0.6 build 210713 or later; QGD-1600P/QGD-1602P: QuNetSwitch 1.0.6.1509 or later; QGD-3014PT: QuNetSwitch 1.0.6.1519 or later
Vendor Advisory: https://www.qnap.com/en/security-advisory/qsa-21-37
Restart Required: Yes
Instructions:
1. Log into QNAP switch management interface. 2. Navigate to firmware update section. 3. Download and install the patched firmware version for your specific model. 4. Reboot the switch after installation completes.
🔧 Temporary Workarounds
Network Segmentation
allRestrict network access to switch management interfaces to trusted networks only
Access Control Lists
allImplement ACLs to block unauthorized access to switch management ports
🧯 If You Can't Patch
- Isolate affected switches in a separate VLAN with strict access controls
- Monitor network traffic to switch management interfaces for suspicious access attempts
🔍 How to Verify
Check if Vulnerable:
Check firmware version in switch web interface or via SSH: show versionCheck Version:
show version (via SSH or console)Verify Fix Applied:
Verify firmware version matches or exceeds patched versions listed in vendor advisory📡 Detection & Monitoring
Log Indicators:
- Unauthorized access attempts to switch management interfaces
- Unusual file access patterns on switch storage
Network Indicators:
- Unexpected connections to switch management ports from untrusted sources
- Traffic patterns indicating data exfiltration from switch
SIEM Query:
source_ip NOT IN trusted_networks AND dest_port IN [switch_management_ports]