CVE-2023-3725
📋 TL;DR
A buffer overflow vulnerability exists in the Zephyr RTOS CAN bus subsystem, allowing attackers to execute arbitrary code or cause denial of service. This affects embedded systems and IoT devices running vulnerable Zephyr versions with CAN bus functionality enabled.
💻 Affected Systems
- Zephyr RTOS
📦 What is this software?
Zephyr by Zephyrproject
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete device compromise, data exfiltration, or device bricking
Likely Case
Denial of service causing device crashes or instability in CAN bus communications
If Mitigated
Limited impact if CAN bus is isolated from untrusted networks and proper input validation is implemented
🎯 Exploit Status
Exploitation requires CAN bus access and knowledge of target system architecture
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Zephyr RTOS 3.2.0 and later
Vendor Advisory: https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-2g3m-p6c7-8rr3
Restart Required: Yes
Instructions:
1. Update Zephyr RTOS to version 3.2.0 or later. 2. Rebuild and redeploy firmware. 3. Restart affected devices.
🔧 Temporary Workarounds
Disable CAN bus subsystem
allDisable CAN bus functionality if not required
CONFIG_CAN=n in prj.conf or Kconfig
Implement CAN bus network segmentation
allIsolate CAN bus networks from untrusted networks
🧯 If You Can't Patch
- Implement strict CAN bus message filtering and validation
- Deploy network monitoring for anomalous CAN bus traffic patterns
🔍 How to Verify
Check if Vulnerable:
Check Zephyr version and CAN bus configuration: grep -r 'CONFIG_CAN=y' && cat VERSIONCheck Version:
cat VERSIONVerify Fix Applied:
Verify Zephyr version is 3.2.0 or later: cat VERSION | grep -E '^3\.[2-9]|^[4-9]'📡 Detection & Monitoring
Log Indicators:
- CAN bus subsystem crashes
- Memory corruption errors
- Unexpected device reboots
Network Indicators:
- Unusual CAN bus message patterns
- Malformed CAN frames
- Excessive CAN bus traffic
SIEM Query:
source="can_bus_logs" AND (event_type="crash" OR message="buffer overflow")🔗 References
- http://packetstormsecurity.com/files/175657/Zephyr-RTOS-3.x.0-Buffer-Overflows.html
- http://seclists.org/fulldisclosure/2023/Nov/1
- http://www.openwall.com/lists/oss-security/2023/11/07/1
- https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-2g3m-p6c7-8rr3
- http://packetstormsecurity.com/files/175657/Zephyr-RTOS-3.x.0-Buffer-Overflows.html
- http://seclists.org/fulldisclosure/2023/Nov/1
- http://www.openwall.com/lists/oss-security/2023/11/07/1
- https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-2g3m-p6c7-8rr3
