Bluetooth Low Energy is key building block of the Internet of Things, that enables simple and efficient monitoring both human and surroundings. BLE technology is implemented in most modern mobile devices and sensor systems. Its use ranges from the field of sports, monitoring surrounding characteristics to house automation, retail industry ... Question is created against daily meeting with such devices, if we could design a solution, that would be able to capture traffic and use it when necessary. As well as to what conclusion could we come with passive sniffing of advertising and connection packages between two devices.
In the thesis I presented the wireless personal area network communication of Bluetooth Low Energy system. I briefly described the protocol stack that provides the foundation for understanding the basic working concept of the system. I also touched traffic capturing, its purpose and security aspects. Especially with the role of passive sniffing and found that the legacy system has flaws in the key exchange protocol to encrypt communications.
I evolved the topic at a practical level with the module Bluefruit LE Sniffer and associated tools and programming libraries and researched their functionality. Based on the sniffer I made the application in the Python programming language, which passively monitors and capture both advertised and connection packages, all the captured traffic is then written on the computer. The application also provides a tool for analyzing the captured traffic which can simply demonstrate active devices within sniffer range.
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