jiska

Wireless connectivity is an integral part of almost any modern device. These technologies include LTE, Wi-Fi, Bluetooth, and NFC. Attackers in wireless range can send arbitrary signals, which are then processed by the chips and operating systems of these devices. Wireless specifications and standards for those technologies are thousands of pages long, and thus pose a large attack surface.

Wireless exploitation is enabled by the technologies any smartphone user uses everyday. Without wireless connectivity our devices are bricked. While we can be more careful to which devices and networks we establish connections to protect ourselves, we cannot disable all wireless chips all the time. Thus, security issues in wireless implementations affect all of us. Wireless chips run a firmware that decodes wireless signals and interprets frames. Any parsing error can lead to code execution within the chip. This is already sufficient to read data passing the chip in plaintext, even if it would be encrypted while transmitted over the air. We will provide a preview into a new tool that enables full-stack Bluetooth fuzzing by real-time firmware emulation, which helps to efficiently identify parsing errors in wireless firmware. Since this kind of bug is within the wireless chips' proprietary firmware, patching requires assistance of the manufacturer. Often, fixing this type of security issue takes multiple months, if done at all. We will tell about our own responsible disclosure experiences, which are both sad and funny. Another risk are drivers in the operating system, which perform a lot of operations on the data they receive from the wireless chip. Most drivers trust the input they get from a wireless chip too much, meaning that wireless exploitation within the chip can easily escalate into the driver. While escalating directly into the operating system is the commonly known option, it is also possible to escalate into other chips. This is a new attack type, which cannot be filtered by the operating system. For everyone who is also concerned during our talk, there will be fancy tin foil hats.

Broadcom's Bluetooth firmware on popular devices – such as Nexus 5, Nexus 6P, Raspberry Pi 3, and Raspberry Pi 3+ – shares the same firmware update mechanisms, which allows for local firmware modifications. With InternalBlue we published a framework to change lower Bluetooth layers. In this talk we go even further and demonstrate a remote exploit in the Broadcom firmware.

In the first part of this talk we present the InternalBlue framework, which allows to experiment with Broadcom-based Bluetooth chips. On Nexus 5 and 6P, it already supports monitoring and injection tools for the lower layers of the Bluetooth protocol stack. The second part of this talk focuses on security. We show how behavior during pairing can be modified, e.g. by setting other device features or IO capabilities. We also demonstrate an implementation of the recent publicly known ECDH key exchange attack. Last, we demonstrate a new attack (CVE-2018-19860) that can crash the Bluetooth stack and execute a limited set of functions – only requiring knowledge of the Bluetooth MAC address of the device under attack. This vulnerability has silently been patched in newer firmware versions, but it applies to Broadcom chips in popular devices such as Nexus 5, Raspberry Pi 3, iPhone 6, Xperia Z5, Samsung Galaxy Note 3, MacBook Pro 2016 and more.

Other people: mantz

Security architectures for wearables are challenging. We take a deeper look into the widely-used Fitbit fitness trackers. The Fitbit ecosystem is interesting to analyze, because Fitbit employs security measures such as end-to-end encryption and authentication to protect user data (and the Fitbit business model). Even though this goes beyond security mechanisms offered by other fitness tracker vendors, reverse-engineering the trackers enables us to launch practical attacks against Fitbit. In our talk, we demonstrate new attacks including wireless malware flashing on trackers as well as “unlocking” the trackers to work independent from the Fitbit cloud.

We explain the Fitbit security architecture, including the most important communication paradigms between tracker, app, and server. Our talk focuses on the tracker itself and its wireless interfaces, nevertheless it is important to understand the roles of the other components to successfully imitate them. Custom firmware makes fitness trackers the ultimate geek toy, including the possibility to improve security and privacy. We show how we reverse-engineered the wireless firmware flashing process, as well as setting up a Nexmon-based environment for developing custom firmware. A short demo shows how wireless flashing works, including potentials of the modified firmware. We also release a smartphone application supporting a subset of the demonstrated attacks, including the possibility for users to extract some of their fitness tracker data without sharing it with Fitbit. This is a huge step towards privacy on wearables. Apart from the app we will also release everything necessary to patch your Fitbit firmware, enabling users to develop more secure mechanisms protecting their data.

Other people: DanielAW

This talk gives an overview on state-of-the-art wireless security concepts: How can we analyze wireless protocols? How can we build mechanisms that are secure even when the attacker has unlimited computational power? Can we exploit wireless transmission for more?

Typically, wireless security is realized by implementing encryption on upper layers and replacing the wire with some wireless modulation schemes. Yet, there is more! For example, it is possible to build "NSA proof" systems or to use legacy WiFi frames as radar. First, there will be a brief introduction on how to hack things with your rad1o badge and other cheap software defined radios. This is your chance to understand how radio waves look like and how to capture and process them :) Second, the concept of wireless physical layer security is introduced. Based on this, information-theoretic secure systems for confidential communication and key exchange can be built. Third, wireless transmissions contain a lot of additional information, since they get disturbed depending on the environment. Hence, we can extract positions of humans and even loudspeaker movements through walls.