[Cryptography] Keeping Malware from Using Security Hardware

[Peter Gutmann]

Kent Borg <kentborg at borg.org> writes:

>But the hardware wallet doesn't understand their multiple approval stuff, so
>what was presented on the hardware wallets was a series of API calls complete
>with parameters, and it sounds like lots of hex.

This is common with HSMs, a lot of the controls are enforced by external API
wrappers, so to bypass them you just go one level lower in the API.  A
security researcher I know once extracted keys from an H$$$M multiple times
simply by going one level further down in the interface each time, Java ->
PKCS #11 -> native API -> bits on the wire.

An old reference but I talked about the issue of problems with different API
levels in HSMs at Usenix Security 2000,
https://www.cs.auckland.ac.nz/~pgut001/pubs/usenix00_slides.pdf

Peter.