* Posts by ZX_Simon

1 publicly visible post • joined 23 Mar 2024

Hardware-level Apple Silicon vulnerability can leak cryptographic keys

ZX_Simon

Limited Real World Effect

The attack takes many operations under the same key to recover the key so is not applicable to things like ephemeral keys used in TLS. The efficiency cores in the M-series chips are also unaffected by this attack as they don't have a data memory-dependent pre-fetcher. Therefore one mitigation for the M1 to M3 series where the pre-fetcher can't be disabled on the performance cores would be to make sure that crypto operations are only done using the efficiency cores.

It is an interesting academic piece of work, however the attack is only approaching anything like a practical exploit where one is repeatedly encrypting or signing with a long term key. Most likely real world scenario would be a server TLS key on a VPS where other VPS instances run on the same machine thus allowing the malicious code to run the attack.