CVE-2021-21903
📋 TL;DR
This critical vulnerability allows remote attackers to execute arbitrary code on Garrett Metal Detectors' iC Module CMA systems by sending specially-crafted UDP packets. The stack-based buffer overflow in the check_udp_crc function can lead to complete system compromise. Organizations using these metal detector systems in security-sensitive environments are affected.
💻 Affected Systems
- Garrett Metal Detectors iC Module CMA
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Complete system takeover with root privileges, allowing attackers to disable security systems, manipulate detection data, or pivot to other network systems.
Likely Case
Remote code execution leading to system disruption, data manipulation, or installation of persistent backdoors on metal detector systems.
If Mitigated
Limited impact if systems are isolated in protected networks with strict firewall rules blocking UDP traffic to vulnerable ports.
🎯 Exploit Status
The vulnerability is straightforward to exploit with publicly available technical details. Attackers can craft malicious UDP packets to trigger the buffer overflow.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Contact Garrett Metal Detectors for updated firmware
Vendor Advisory: https://www.garrett.com/security-advisory
Restart Required: Yes
Instructions:
1. Contact Garrett Metal Detectors support for patched firmware. 2. Backup current configuration. 3. Apply firmware update following vendor instructions. 4. Restart the iC Module CMA system. 5. Verify functionality.
🔧 Temporary Workarounds
Network Segmentation
allIsolate iC Module CMA systems in separate VLANs with strict firewall rules
Firewall Restrictions
linuxBlock all UDP traffic to the vulnerable port on affected systems
iptables -A INPUT -p udp --dport [PORT] -j DROP
🧯 If You Can't Patch
- Segment affected systems in isolated network zones with no internet access
- Implement strict network monitoring for anomalous UDP traffic patterns
🔍 How to Verify
Check if Vulnerable:
Check system firmware version via device management interface. If version is 5.0, system is vulnerable.Check Version:
Check via device web interface or serial console (specific command depends on access method)Verify Fix Applied:
Verify firmware version has been updated to a version later than 5.0 via device management interface.📡 Detection & Monitoring
Log Indicators:
- Unusual UDP packet patterns
- System crash/restart events
- Memory access violation logs
Network Indicators:
- Malformed UDP packets to port used by iC Module CMA
- Unusual traffic spikes to metal detector systems
SIEM Query:
source="firewall" AND dest_port=[PORT] AND protocol="UDP" AND packet_size>normal_threshold