CVE-2023-4258
📋 TL;DR
This vulnerability allows an attacker to impersonate a legitimate device during Bluetooth mesh provisioning by replaying a previously captured public key. It affects Bluetooth mesh implementations that use out-of-band (OOB) public key exchange, particularly in Zephyr RTOS-based IoT devices.
💻 Affected Systems
- Zephyr RTOS Bluetooth mesh implementation
📦 What is this software?
Zephyr by Zephyrproject
⚠️ Risk & Real-World Impact
Worst Case
An attacker could join malicious devices to a Bluetooth mesh network, intercept communications, inject false data, or disrupt network operations entirely.
Likely Case
Unauthorized device provisioning leading to network infiltration and potential data interception in vulnerable IoT deployments.
If Mitigated
Limited impact if network segmentation and device authentication controls are properly implemented alongside patching.
🎯 Exploit Status
Requires proximity to Bluetooth mesh network and ability to capture OOB public key exchange.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Zephyr v3.4.0 and later
Vendor Advisory: https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-m34c-cp63-rwh7
Restart Required: Yes
Instructions:
1. Update Zephyr RTOS to v3.4.0 or later. 2. Rebuild and redeploy firmware to affected devices. 3. Ensure OOB public key exchange is properly validated in custom implementations.
🔧 Temporary Workarounds
Disable OOB public key provisioning
allTemporarily disable out-of-band public key exchange in Bluetooth mesh provisioning
CONFIG_BT_MESH_PROV_OOB_PUBLIC_KEY=n in prj.conf
🧯 If You Can't Patch
- Segment Bluetooth mesh networks from critical infrastructure
- Implement additional device authentication layers beyond Bluetooth mesh provisioning
🔍 How to Verify
Check if Vulnerable:
Check if Zephyr version < 3.4.0 and CONFIG_BT_MESH_PROV_OOB_PUBLIC_KEY is enabledCheck Version:
grep ZEPHYR_VERSION build/zephyr/include/generated/version.hVerify Fix Applied:
Verify Zephyr version >= 3.4.0 and test provisioning with OOB public key exchange📡 Detection & Monitoring
Log Indicators:
- Unexpected device provisioning events
- Multiple provisioning attempts from same public key
Network Indicators:
- Unauthorized devices appearing in mesh network
- Abnormal provisioning traffic patterns
SIEM Query:
bluetooth AND mesh AND (provisioning OR oob) AND (public_key OR replay)