CVE-2023-6249
📋 TL;DR
CVE-2023-6249 is an incorrect type conversion vulnerability in the Zephyr RTOS esp32_ipm_send function, where a signed integer is improperly converted to unsigned without bounds checking. This allows attackers to cause buffer overflows or memory corruption, potentially leading to denial of service or arbitrary code execution. It affects systems running Zephyr RTOS on ESP32 hardware with the vulnerable IPM (Inter-Processor Messaging) functionality enabled.
💻 Affected Systems
- Zephyr RTOS
📦 What is this software?
Zephyr by Zephyrproject
Zephyr by Zephyrproject
Zephyr by Zephyrproject
Zephyr by Zephyrproject
Zephyr by Zephyrproject
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to complete system compromise, privilege escalation, or persistent backdoor installation on affected ESP32 devices.
Likely Case
System crash, denial of service, or unstable behavior due to memory corruption and buffer overflow conditions.
If Mitigated
Limited impact with proper memory protection mechanisms and sandboxing, potentially causing only application crashes.
🎯 Exploit Status
Exploitation requires sending specially crafted IPM messages to trigger the type conversion issue. The attacker needs access to send IPM messages, which typically requires some level of system access.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Zephyr v3.5.0 and later
Vendor Advisory: https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-32f5-3p9h-2rqc
Restart Required: Yes
Instructions:
1. Update Zephyr RTOS to version 3.5.0 or later. 2. Rebuild your application with the updated Zephyr SDK. 3. Flash the updated firmware to affected ESP32 devices. 4. Restart the devices to apply the fix.
🔧 Temporary Workarounds
Disable IPM functionality
allDisable Inter-Processor Messaging if not required for your application
CONFIG_IPM=n in your project configuration
Add bounds checking
allImplement manual bounds checking in application code before calling esp32_ipm_send
🧯 If You Can't Patch
- Implement network segmentation to isolate affected ESP32 devices from untrusted networks
- Deploy intrusion detection systems to monitor for abnormal IPM message patterns
🔍 How to Verify
Check if Vulnerable:
Check Zephyr version and IPM configuration: 1. Run 'west config' to check Zephyr version. 2. Verify CONFIG_IPM is enabled in project configuration. 3. Check if running on ESP32 hardware.Check Version:
west config | grep 'zephyr.base' && cd $(west config | grep 'zephyr.base' | cut -d'=' -f2) && git describe --tagsVerify Fix Applied:
1. Confirm Zephyr version is 3.5.0 or later with 'west config'. 2. Verify the fix commit is included: check for commit addressing CVE-2023-6249 in git history. 3. Test IPM functionality to ensure no crashes occur.📡 Detection & Monitoring
Log Indicators:
- IPM message handling errors
- Memory access violation logs
- System crash/reboot events
- ESP32 watchdog resets
Network Indicators:
- Unusual IPM message patterns
- Excessive inter-processor communication
- Abnormal ESP32 network behavior
SIEM Query:
source="zephyr_logs" AND ("IPM error" OR "memory violation" OR "watchdog reset")