Revision as of 15:44, 5 December 2024

Description

Description what this documentation is about.

Bluetooth LE

GAP - Generic Attribute Profile

The Generic attribute profile takes care of discovery, security, connectivity and network technolgies of a device as well as it's role. These are examples of packages during pairing:

ADV_IND
SCAN_REQ
SCAN_RSP
CONNECT_IND
AUX_SCAN_REQ
AUX_SCAN_RSP
AUX_CONNECT_REQ
AUX_CONNECT_RSP
ADV_SCAN_IND

GATT - Generic Attribute Profile

As soon as two Bluetooth Low Energy devices establish a connection they can start transfering data back and forth. This data is formated into Services and Characteristics in a Server/Client relationship.

Network Topology

The network topology of GATT networks contains so-called central devices and peripheral devices. One peripheral is only connected to only one central device at a time. A central device can connect to many peripheral devices. The peripheral is also acting as the GATT server. It contains the definitions for profiles, services and characteristics of a device. The central device always initiates the data exchange.

ATT - Attribute Protocol

GATT is based on ATT. Each attribute gets it’s own Unique Identifier (UUID) here. These get formatted as characteristics and services.

Profiles

set of services per Profile Example profiles: Basic audio profile, Location and navigation profile, weight scale profile, heart rate profile

Services

A Service can have multiple characteristics. It has it’s own UUID. It has a handle. UUID, permissions, value

Characteristics

The characteristics are the lowest-level of the GATT Profiles. They also each use their own UUID. These are relevant when it comes to protecting and enhancing security of a Bluetooth Low Energy device. The characteristics have a value, properties and human-readable descriptors

Example UUIDs of a Polar Smartwatch

Example Device UUID:

C6C36C4A-7F8F-52B2-2BD7-C4F6690424E7

Example Service UUIDs:

Service: 0000180a-0000-1000-8000-00805f9b34fb (Handle: 14): Device Information
Service: 0000feee-0000-1000-8000-00805f9b34fb (Handle: 29): Polar Electro Oy
Service: 0000180d-0000-1000-8000-00805f9b34fb (Handle: 38): Heart Rate
Service: 0000180f-0000-1000-8000-00805f9b34fb (Handle: 42): Battery Service

Example Service and their Characteristics UUIDs including handles, permissions, properties, values, descriptors:

Service: 0000180a-0000-1000-8000-00805f9b34fb (Handle: 14): Device Information
 Characteristic: 00002a29-0000-1000-8000-00805f9b34fb (Handle: 15) - Properties: ['read']
 Characteristic: 00002a24-0000-1000-8000-00805f9b34fb (Handle: 17) - Properties: ['read']
 Characteristic: 00002a25-0000-1000-8000-00805f9b34fb (Handle: 19) - Properties: ['read']
 Characteristic: 00002a27-0000-1000-8000-00805f9b34fb (Handle: 21) - Properties: ['read']
 Characteristic: 00002a26-0000-1000-8000-00805f9b34fb (Handle: 23) - Properties: ['read']
 Characteristic: 00002a28-0000-1000-8000-00805f9b34fb (Handle: 25) - Properties: ['read']
 Characteristic: 00002a23-0000-1000-8000-00805f9b34fb (Handle: 27) - Properties: ['read']
Service: 0000feee-0000-1000-8000-00805f9b34fb (Handle: 29): Polar Electro Oy
 Characteristic: fb005c51-02e7-f387-1cad-8acd2d8df0c8 (Handle: 30) - Properties: ['write-without-response', 'write', 'notify']
 Characteristic: fb005c52-02e7-f387-1cad-8acd2d8df0c8 (Handle: 33) - Properties: ['notify']
 Characteristic: fb005c53-02e7-f387-1cad-8acd2d8df0c8 (Handle: 36) - Properties: ['write-without-response', 'write']
Service: 0000180d-0000-1000-8000-00805f9b34fb (Handle: 38): Heart Rate
 Characteristic: 00002a37-0000-1000-8000-00805f9b34fb (Handle: 39) - Properties: ['notify']
Service: 0000180f-0000-1000-8000-00805f9b34fb (Handle: 42): Battery Service
 Characteristic: 00002a19-0000-1000-8000-00805f9b34fb (Handle: 43) - Properties: ['read', 'notify']

BLE Operations

Read

Read the data of a characteristic

Write

Write data to a characteristic

Notify

Get notifications to value changes of a device by subscribing to it

Further Context

Make sure to read

Setting Up Ubertooth on macOS for Bluetooth Hacking [1]

Courses

Selected IT-Security Chapters (2024)

Author

Are Maksimović

References

@@ Line 7: / Line 7: @@
 == GAP - Generic Attribute Profile ==
-The Generic attribute profile takes care of discovery, security, connectivity and network technolgies of a device.
+The Generic attribute profile takes care of discovery, security, connectivity and network technolgies of a device as well as it's role. These are examples of packages during pairing:
   ADV_IND