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To prevent downgrade attacks, include a list of banned signatures/hashes of previous versions in an upgrade? Plus only allow higher version numbers? Downside:
by okket 10y ago
To prevent downgrade attacks, include a list of banned signatures/hashes of previous versions in an upgrade? Plus only allow higher version numbers?
Downside: Reverting is not possible if you make a serious mistake in an upgrade. If you can't initiate another upgrade process, bricking is possible...
I don't know much about the world of really small devices aka IoT, but from my laymen perspective: Is a full TLS stack still a huge obstacle there? Sane signature checks are at least a step in the right direction.
- sneak 10y agoA device running 1.0 could still be upgraded to a vulnerable signed 1.1 when a patched 1.2 with blacklist is current on the site.
- 0x0 10y agoA device running a vulnerable signed 1.1 could still be denied an upgrade to 1.2 by a MITM blocking port 443 even if you used HTTPS.
- peeters 10y agoYeah but it's kind of irrelevant because the device is already vulnerable in your example. The point of this was to say that you can turn a safe device into a vulnerable device as part of a multi-phase attack.