CVE-2021-33016
📋 TL;DR
CVE-2021-33016 allows attackers to gain full read/write/delete access to sensitive folders on KUKA KR C4 industrial control systems due to hard-coded credentials. This affects KUKA KR C4 control software versions prior to 8.7 and any product running KSS (KUKA System Software). Industrial facilities using these vulnerable systems are at risk.
💻 Affected Systems
- KUKA KR C4 control software
- Any product running KUKA System Software (KSS)
📦 What is this software?
Kss by Kuka
⚠️ Risk & Real-World Impact
Worst Case
Complete compromise of industrial control systems allowing attackers to modify robot programming, disrupt manufacturing processes, cause physical damage, or exfiltrate sensitive industrial data.
Likely Case
Unauthorized access to sensitive configuration files, potential disruption of manufacturing operations, and data theft from industrial control systems.
If Mitigated
Limited impact if systems are properly segmented, monitored, and access controlled, though the hard-coded credentials remain a persistent threat.
🎯 Exploit Status
Exploitation is straightforward once the hard-coded credentials are known. The vulnerability is well-documented in public advisories.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Version 8.7 or later
Vendor Advisory: https://www.cisa.gov/uscert/ics/advisories/icsa-21-208-01
Restart Required: Yes
Instructions:
1. Contact KUKA for the latest KR C4 software update. 2. Backup all configurations and programs. 3. Apply KSS 8.7 or later update following KUKA's installation procedures. 4. Restart the control system. 5. Verify the update was successful.
🔧 Temporary Workarounds
Network Segmentation
allIsolate KUKA KR C4 systems from untrusted networks and implement strict firewall rules.
Access Control Lists
allImplement strict network access controls to limit connections to KUKA systems only from authorized engineering stations.
🧯 If You Can't Patch
- Implement strict network segmentation and zero-trust principles around KUKA systems
- Monitor all network traffic to/from KUKA systems for suspicious activity and implement intrusion detection
🔍 How to Verify
Check if Vulnerable:
Check KSS version on the KR C4 controller. Versions below 8.7 are vulnerable. Also check if hard-coded credentials are present in configuration files.Check Version:
Check version through KUKA SmartPAD interface or KSS diagnostic tools (specific commands vary by KSS version)Verify Fix Applied:
Verify KSS version is 8.7 or later. Confirm that hard-coded credentials have been removed or changed in the updated software.📡 Detection & Monitoring
Log Indicators:
- Unauthorized access attempts to sensitive folders
- Authentication attempts using hard-coded credentials
- Unexpected file modifications in system directories
Network Indicators:
- Unexpected connections to KUKA system ports (typically 7000-7002)
- Network traffic patterns indicating file transfers from control systems
SIEM Query:
source_ip="KUKA_System_IP" AND (event_type="file_access" OR event_type="authentication") AND result="failure"