CVE-2024-4785
📋 TL;DR
This vulnerability in Zephyr RTOS Bluetooth stack allows attackers to crash devices via a division by zero error when processing malicious LL_CONNECTION_UPDATE_IND packets. It affects Bluetooth Low Energy (BLE) implementations using vulnerable Zephyr versions, potentially impacting IoT devices, wearables, and embedded systems.
💻 Affected Systems
- Zephyr RTOS Bluetooth stack
📦 What is this software?
Zephyr by Zephyrproject
⚠️ Risk & Real-World Impact
Worst Case
Complete device crash and denial of service, potentially requiring physical reset or causing system instability in critical embedded systems.
Likely Case
Bluetooth stack crash leading to temporary loss of BLE connectivity until system restart or stack recovery.
If Mitigated
Minimal impact with proper input validation and error handling preventing the crash.
🎯 Exploit Status
Exploitation requires sending specially crafted BLE packets to vulnerable devices within Bluetooth range. No authentication needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Fixed in Zephyr RTOS main branch (commit referenced in advisory)
Vendor Advisory: https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-xcr5-5g98-mchp
Restart Required: Yes
Instructions:
1. Update Zephyr RTOS to latest version with the fix. 2. Rebuild and redeploy firmware to affected devices. 3. Restart devices to apply the updated firmware.
🔧 Temporary Workarounds
Disable BLE if not needed
allTemporarily disable Bluetooth Low Energy functionality to prevent exploitation
# Configure device to disable BLE in firmware/configuration
Implement input validation
allAdd validation for LL_CONNECTION_UPDATE_IND packet fields before processing
// In Bluetooth stack code, validate divisor != 0 before division operation
🧯 If You Can't Patch
- Segment network to isolate vulnerable BLE devices from potential attackers
- Implement physical security controls to limit Bluetooth proximity access
🔍 How to Verify
Check if Vulnerable:
Check Zephyr version and verify if Bluetooth stack includes the vulnerable LL_CONNECTION_UPDATE_IND handling codeCheck Version:
Check Zephyr version in build configuration or via device firmware version commandVerify Fix Applied:
Verify the fix commit is included in your Zephyr build and test BLE connectivity with malformed packets📡 Detection & Monitoring
Log Indicators:
- Bluetooth stack crash logs
- Division by zero errors in system logs
- BLE connection failures
Network Indicators:
- Unusual LL_CONNECTION_UPDATE_IND packets
- Multiple BLE connection attempts with malformed packets
SIEM Query:
Search for 'division by zero' OR 'bluetooth crash' OR 'BLE stack error' in device logs