What is Bluetooth Man-in-the-Middle Attack?
A man-in-the-middle attack occurs when an attacker inserts themselves between two devices, intercepting their communication and possibly altering the data, often without the users’ knowledge. In Bluetooth, this typically happens with Bluetooth Low Energy (BLE) devices, such as smartwatches.
How the attack is carried out:
1.The attacker must be within the signal range of the Bluetooth devices, usually within10 meters.
2.When a device attempts to connect, the attacker intercepts the connection request.
3.The attacker pretends to be one of the devices, establishing a connection with the other device. For example, pretending to be a smartphone connecting to a smartwatch while also pretending to be the smartwatch connecting to the actual smartphone.
4.The attacker forwards all data between the two devices, allowing them to view or modify the content, such as stealing health data or sending false commands.
Why is it easy to be attacked?
During the Bluetooth connection process, there may not be strict authentication, which attackers can exploit, especially when devices are not encrypted or not properly paired.
What tools can be used to implement this?
Research shows that the following tools can be used to simulate or execute Bluetooth man-in-the-middle attacks:
Ubertooth: This is a software-defined radio platform that can capture and analyze Bluetooth traffic, suitable for security research.
Other software-defined radio platforms: such asHackRF, which can send and receive data on Bluetooth frequencies.Nordic Connect APP.
Custom tools: Security researchers may develop scripts to exploit known vulnerabilities.
Detailed analysis and tools for Bluetooth man-in-the-middle attacks
Bluetooth is a widely used wireless communication technology, especially in smart devices like smartwatches. However, research shows that Bluetooth communication, particularly Bluetooth Low Energy, is vulnerable to man-in-the-middle attacks. Such attacks can lead to the leakage of sensitive data, such as health information or location data, posing threats to user privacy and device security.
If your smartwatch is attacked during a workout, and the attacker steals your heart rate data and alters your fitness records, it significantly impacts your experience. Therefore, understanding the process and tools of man-in-the-middle attacks is crucial.
Why should we care about Bluetooth security?
Bluetooth device cybersecurity is regulated by the EU Radio Equipment Directive, meaning that devices capable of connecting to the internet and processing personal information must have protections. Additionally, theIEC 81001-5-1 standard also applies to smartwatches handling health data, raising security requirements.
What is a man-in-the-middle attack?
A man-in-the-middle attack occurs when an attacker quietly inserts themselves between two devices, either eavesdropping or tampering with their communication. For Bluetooth, especially in Bluetooth Low Energy mode, the attack process is as follows:
The attacker must be within the Bluetooth signal range, generally10 meters (classic Bluetooth) or further (depending on the device type). Bluetooth Low Energy uses frequency hopping spread spectrum, but if the attacker knows the hopping sequence, they can intercept the communication.
When a smartwatch attempts to connect to a smartphone, the attacker intercepts the connection request. Bluetooth Low Energy connections are based on device addresses, and without strong authentication, the attacker can impersonate a device.
The attacker pretends to connect the smartphone and smartwatch while also pretending to connect the smartwatch to the actual smartphone, acting as a relay.
The attacker forwards all data, allowing them to view or modify it. For example, stealing heart rate data or sending a false command.
Exploiting vulnerabilities: The Bluetooth Low Energy connection process may lack authentication, especially in the“just works” pairing mode, making it easy for attackers to insert themselves.
For instance, the Bluetooth man-in-the-middle vulnerability discovered in2014 allowed attackers to intercept your communication while pairing Bluetooth devices.
Current Bluetooth Low Energy technology is relatively secure, with simple pairing methods like numeric comparison, but if you do not verify carefully, attackers still have opportunities to succeed.
A surprising detail: even if your device is already paired and encrypted (for example, usingAES encryption), if the attacker intervenes before pairing, they may obtain the key and monitor your communication long-term. This poses a continuous threat to devices used over extended periods (like smartwatches).
Tool selection: Tools in security research
Research shows that the following tools can be used to simulate or execute Bluetooth man-in-the-middle attacks:
Ubertooth: This is a software-defined radio platform designed specifically for Bluetooth security research, capable of capturing and analyzing traffic, particularly suitable for injection attacks.
HackRF: This is a general-purpose software-defined radio tool that can send and receive data on Bluetooth frequencies (2.4 GHz), particularly suitable for intercepting and modifying communications.
Bleah: This is a tool specifically for Bluetooth Low Energy, capable of performing connection hijacking and data interception, particularly suitable for studying man-in-the-middle attacks.
Wireshark: When combined with Bluetooth Low Energy decoders, it can passively capture traffic, but for active attacks, it needs to be used with other tools.
Custom scripts: Security researchers develop scripts based on known vulnerabilities, similar to the methods mentioned in the2016 paper.
To successfully attack, the device settings are crucial, such as not enabling encryption or using insecure pairing methods.
Example: Security vulnerabilities in smartwatches
Take the“HealthWatch” smartwatch as an example. If Bluetooth communication is not encrypted, hackers can useUbertooth to intercept heart rate data, alter fitness records, and affect users’ health decisions. Research shows that the man-in-the-middle attack mentioned in the2016 paper can steal users’ account passwords and health information, necessitating penetration testing.
It is recommended to upgrade toAES-256 encryption, use secure and simple pairing methods, and regularly update software to reduce risks.
Conclusion and Future Outlook
The process of Bluetooth man-in-the-middle attacks includes intercepting connections, impersonating devices, and forwarding communications, achievable with tools likeUbertooth andHackRF, but they must be used legally. In the future, as Bluetooth Low Energy devices proliferate, the risk of attacks will increase, so it is advisable to prepare for compliance, such as adhering toIEC 81001-5-1 andEN 18031 standards to ensure device security.