CVE-2021-27289
📋 TL;DR
This vulnerability allows attackers within wireless range to replay captured Zigbee packets with manipulated sequence numbers, bypassing anti-replay protection. Attackers can inject spoofed commands to trigger false alerts and manipulate smart home device behavior. Users of Ksix Zigbee smart home kits with specific firmware versions are affected.
💻 Affected Systems
- Ksix Zigbee Gateway Module
- Ksix Zigbee Door Sensor
- Ksix Zigbee Motion Sensor
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Attacker gains complete control over smart home devices, triggering false security alerts, disabling legitimate alarms, or creating dangerous conditions by manipulating sensors.
Likely Case
False alerts and notifications in the mobile app, misleading users about security status, and potential denial of service for legitimate sensor functions.
If Mitigated
Limited impact with proper network segmentation and monitoring, though false alerts may still occur.
🎯 Exploit Status
Exploitation requires physical proximity to capture packets. Multiple public proof-of-concept tools and videos demonstrate the attack.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Unknown
Vendor Advisory: None found
Restart Required: No
Instructions:
No official patch available. Contact Ksix support for firmware updates if they become available.
🔧 Temporary Workarounds
Network Segmentation
allIsolate Zigbee network from other networks to limit attack surface
Physical Security
allRestrict physical access to wireless range of devices
🧯 If You Can't Patch
- Replace affected devices with models from vendors that implement proper Zigbee security
- Disable affected devices and use alternative security monitoring solutions
🔍 How to Verify
Check if Vulnerable:
Check device firmware versions via mobile app or device labeling. Gateway Module v1.0.3, Door Sensor v1.0.7, Motion Sensor v1.0.12 are vulnerable.Check Version:
Check via Ksix mobile application or physical device labelingVerify Fix Applied:
Verify firmware has been updated to versions not listed as vulnerable. No known fixed versions available.📡 Detection & Monitoring
Log Indicators:
- Unexpected sensor activations
- Multiple identical alerts in rapid succession
- Alerts from sensors that should be inactive
Network Indicators:
- Unusual Zigbee packet patterns
- Repeated identical frames with different sequence numbers
- Packets with abnormally high frame counters
SIEM Query:
Zigbee traffic analysis showing frame counter anomalies or replay patterns🔗 References
- https://github.com/TheMalwareGuardian/CVE-2021-27289
- https://packetstormsecurity.com/files/160331/Ksix-Zigbee-Devices-Playback-Protection-Bypass.html
- https://www.exploit-db.com/exploits/49169
- https://www.youtube.com/watch?v=5IFUpRKEioA
- https://www.youtube.com/watch?v=XFOy3wSlC9Q
- https://www.youtube.com/watch?v=yc9IEt5IMmA
