ShapeShift Security Update

Our response to the disclosed KeepKey vulnerability.

On May 1st, 2019, ShapeShift received a report from Christian Reitter through our Responsible Disclosure Program that identified what they believed to be a vulnerability in KeepKey. This report was part of a coordinated disclosure across multiple hardware wallet vendors, and the vulnerability has since been assigned tracking number CVE-2019–14355 by Mitre. Security is obviously one of our highest priorities at ShapeShift, so we’ve reviewed the report to better understand the vulnerability in detail.

“We believe there is insignificant risk to ShapeShift users, their KeepKeys, and their funds. “ — ShapeShift’s Security Team

Here’s How it Works

KeepKey’s screen uses power. By measuring the subtle differences in the amount of power used by the screen at any moment, it is possible to identify what is being displayed. This is called a side-channel attack. While the attack is not reading the screen directly (it’s only reading power fluctuations), an attacker can figure out what is on the screen anyway. If this is done while sensitive information is on the screen (like your recovery phrase), an attacker could ultimately steal your funds.

Here’s What Would Need to Happen

An attacker needs the following in order to perform this attack:

Physical Access — They need your KeepKey in their hands to make this work

— They need your KeepKey in their hands to make this work Specialized Equipment — They need an oscilloscope or another device capable of measuring the minute differences in the power drawn from the screen

— They need an oscilloscope or another device capable of measuring the minute differences in the power drawn from the screen Hardware Skills — They need the ability to measure the electrical signals on the USB interface without disrupting it

— They need the ability to measure the electrical signals on the USB interface without disrupting it Statistical Data — A lot of work and analysis is required to understand how much power is drawn from each seed word

That’s a lot of stuff… and again the attacker needs to physically possess your KeepKey.

By comparison, it would be far easier to steal someone’s Recovery Phrase by simply looking over their shoulder while they set up their KeepKey or installing a hidden camera in the room in which it was being initialized. It is impossible to stop someone from tampering with any hardware wallet if they have it in their hands. We discussed this in June on our blog after Ledger presented their research at Breaking Bitcoin. In other words, if you care about actual risk, there are far more important things to be concerned with, such as the physical environment in which you initialize and use your hardware device.

KeepKey Not Materially Affected

After analyzing this attack in-depth, we believe KeepKey is not affected: