Detecting Bluetooth Low Energy Attacks

Disclaimer

This skill is intended for authorized security testing, penetration testing engagements, CTF competitions, and educational purposes only. Sniffing, intercepting, or manipulating Bluetooth communications without authorization may violate federal wiretapping laws and local regulations. Always obtain explicit written permission before conducting any wireless security assessment.

When to Use

Use this skill when:

• Performing authorized BLE security assessments of IoT devices, medical devices, or smart locks
• Monitoring a wireless environment for BLE-based replay attacks, spoofing, or unauthorized enumeration
• Analyzing BLE packet captures to detect Man-in-the-Middle attacks or pairing exploitation
• Enumerating GATT services and characteristics to identify insecure read/write permissions on BLE peripherals
• Assessing BLE encryption strength and testing for crackable pairing exchanges
• Building BLE intrusion detection capabilities for wireless security monitoring

Do not use for intercepting BLE communications without explicit authorization. Do not deploy BLE scanning tools in environments where wireless monitoring is prohibited.

Prerequisites

• Ubertooth One hardware for passive BLE sniffing, or Nordic nRF52840 USB Dongle with nRF Sniffer firmware
• Python 3.10+ with pip
• bleak library: pip install bleak (cross-platform BLE GATT client)
• Wireshark with BLE dissector plugins for packet analysis
• crackle tool for BLE encryption analysis: built from source at github.com/mikeryan/crackle
• ubertooth-btle CLI tools: apt install ubertooth (Linux) or build from source
• Bluetooth 4.0+ adapter on the host system for bleak-based scanning
• Linux recommended for full Ubertooth/nRF sniffer support

Workflow

Step 1: BLE Environment Discovery and Device Scanning

Scan the environment to identify BLE devices and their advertising data:

# Scan for BLE devices using bleak (cross-platform)
python -c "
import asyncio
from bleak import BleakScanner

async def scan():
    devices = await BleakScanner.discover(timeout=10.0)
    for d in devices:
        print(f'{d.address} | RSSI: {d.rssi} | Name: {d.name or \"Unknown\"}')
        for uuid in d.metadata.get('uuids', []):
            print(f'  Service: {uuid}')

asyncio.run(scan())
"

# Passive BLE sniffing with Ubertooth One (promiscuous mode)
ubertooth-btle -p -r capture.pcapng

# Follow a specific BLE connection
ubertooth-btle -f -t AA:BB:CC:DD:EE:FF -r connection.pcapng

# Use nRF Sniffer with Wireshark (via extcap interface)
wireshark -i nRF_Sniffer -k

Step 2: GATT Service and Characteristic Enumeration

Connect to target BLE peripherals and enumerate their GATT profile:

# Enumerate all services, characteristics, and descriptors
python -c "
import asyncio
from bleak import BleakClient

async def enum_gatt(address):
    async with BleakClient(address) as client:
        print(f'Connected: {client.is_connected}')
        for service in client.services:
            print(f'Service: {service.uuid} - {service.description}')
            for char in service.characteristics:
                props = ','.join(char.properties)
                print(f'  Char: {char.uuid} | Props: {props}')
                for desc in char.descriptors:
                    val = await client.read_gatt_descriptor(desc.handle)
                    print(f'    Desc: {desc.uuid} = {val}')

asyncio.run(enum_gatt('AA:BB:CC:DD:EE:FF'))
"

Security-relevant findings during GATT enumeration:

• Characteristics with write-without-response or write without authentication
• Readable characteristics exposing device configuration, credentials, or firmware versions
• Missing Client Characteristic Configuration Descriptor (CCCD) protection on notification characteristics

Step 3: BLE Packet Capture and Analysis

Capture BLE traffic for offline analysis:

# Capture with Ubertooth in PcapNG format (recommended)
ubertooth-btle -f -r capture.pcapng

# Capture in PCAP/PPI format for crackle compatibility
ubertooth-btle -f -c capture_ppi.pcap

# Analyze capture in Wireshark
wireshark capture.pcapng
# Apply display filter: btle
# Filter connection requests: btle.advertising_header.pdu_type == 0x05
# Filter data packets: btle.data_header

# Extract pairing information with tshark
tshark -r capture.pcapng -Y "btle.control_opcode == 0x01" -T fields \
  -e btle.master_bd_addr -e btle.slave_bd_addr

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