CVE-2023-5055
📋 TL;DR
CVE-2023-5055 is a stack-based buffer overflow vulnerability in the le_ecred_reconf_req function of Zephyr RTOS Bluetooth LE stack. This allows attackers to execute arbitrary code or cause denial of service by sending specially crafted Bluetooth packets. Affects devices running vulnerable Zephyr RTOS versions with Bluetooth LE 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 Bluetooth functionality disruption or device crashes
If Mitigated
Limited impact if Bluetooth stack is isolated or device has memory protection features
🎯 Exploit Status
Exploitation requires Bluetooth access to target device and knowledge of vulnerable function usage
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: v3.4.0 and later
Vendor Advisory: https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-wr8r-7f8x-24jj
Restart Required: Yes
Instructions:
1. Update Zephyr RTOS to version 3.4.0 or later. 2. Rebuild and redeploy firmware. 3. Restart affected devices.
🔧 Temporary Workarounds
Disable Bluetooth LE Enhanced Connection feature
allDisable the vulnerable Bluetooth LE Enhanced Connection functionality
CONFIG_BT_ECRED=n in project configuration
Implement Bluetooth access controls
allRestrict Bluetooth connections to trusted devices only
🧯 If You Can't Patch
- Segment Bluetooth network from critical systems
- Implement device-level firewall rules to restrict Bluetooth connections
🔍 How to Verify
Check if Vulnerable:
Check Zephyr version and CONFIG_BT_ECRED setting in project configurationCheck Version:
Check Zephyr version in build configuration or device firmware infoVerify Fix Applied:
Verify Zephyr version is 3.4.0+ and check for successful firmware update📡 Detection & Monitoring
Log Indicators:
- Bluetooth stack crashes
- Memory corruption errors
- Unexpected device reboots
Network Indicators:
- Unusual Bluetooth connection attempts
- Malformed Bluetooth packets
SIEM Query:
Search for Bluetooth stack error codes or device crash events related to le_ecred_reconf_req