The manufacturer of popular hardware wallets for storing cryptocurrency Ledger responded to the presentation of the team wallet.fail, which announced the identification of several vectors of attacks on its devices.
In particular they did not succeed to extract any seed nor PIN on a stolen device. Every sensitive assets stored on the Secure Element remain secure. Don’t worry, your crypto assets are still secure on your Ledger device.
In particular, the physical modification of the Ledger Nano S wallet followed by the installation of malware on the victim’s computer and the possibility of signing transactions after entering the PIN code are called “impractical”.
It would prove quite unpractical, and a motivated hacker would definitely use more efficient tricks (such as installing a camera to spy on the PIN entry).
According to the company, obtaining physical access to the device and installing malware on the victim's computer is too complicated and requires the hacker to wait for the user to initiate the transaction, so it is unlikely that anyone will undertake its implementation. At the same time, they do not deny that this is possible.
Another scenario, where the researchers installed their own firmware on a microprocessor, really allows you to put the device into debug mode, said Ledger, adding that the capabilities of the alleged attacker are likely to be limited. “They said they had identified a way to bypass the microprocessor check, but they didn’t show how the bug was used.”
Similarly, developers are commenting on how to extract a PIN from a Ledger Blue device using a “controlled machine learning” attack.
This attack is definitely interesting, but does not allow to guess someone’s PIN in real conditions (it requires that you never move your device at all).
For such a scenario, we already implemented a randomized keyboard for the PIN on the Ledger Nano S, and the same improvement is scheduled in the next Ledger Blue Firmware update.
Once again, a better side channel would be to put a camera in the room and record the user entering his/her PIN.
Ledger also criticized the wallet.fail team for deciding to publicly demonstrate the vulnerabilities of their devices at the conference, rather than resorting to the bug trapping program provided for such cases. "We believe that their conclusions do not indicate the presence of any vulnerabilities that can be used in practice," the company adds.