4 ms·

>But okay, you may extend my attack by saying that you exchange the motherboard between the victim and the attacker laptop, so that you don't need to replicate

>But okay, you may extend my attack by saying that you exchange the motherboard between the victim and the attacker laptop, so that you don't need to replicate the chassis. Modern computers has tamper detection and if you open them you'll need to type the BIOS password. However, replacing the motherboard is going to replace the TPM. This is easily detectable with something like tpm2_totp in the bootchain. https://github.com/tpm2-software/tpm2-totp https://github.com/tpm2-software/tpm2-totp

phh 5y ago
Now we're talking proper security, thanks. > Modern computers has tamper detection and if you open them you'll need to type the BIOS password. Is that somehow configurable from Linux distribution's setup, or it will require user to manually set a BIOS password? (and it requires the user to set a different bios password. if the user sets the same password for fde and for bios, then back to square 1) > However, replacing the motherboard is going to replace the TPM. This is easily detectable with something like tpm2_totp in the bootchain. That sounds interesting. Though it still sounds totally impossible for the vast majority of users. At that point, I don't really know what's the goal of TFA. If it's for extreme power users who want best security, it is missing the various counter-measures mentioned in this thread. If it's about pushing distributions to have better defaults, then I think it's quite moot, because secure boot won't improve security much to average users.
- Foxboron 5y ago
  >Is that somehow configurable from Linux distribution's setup, or it will require user to manually set a BIOS password? (and it requires the user to set a different bios password. if the user sets the same password for fde and for bios, then back to square 1) Not yet? And when I said "modern computers" i should probably clarify I'm thinking about more enterprise grade computers. Such as Thinkpads. Thinkpads also recently got the feature to set the password from Linux userspace. But I forget where I read that, and where the patch is located :) >That sounds interesting. Though it still sounds totally impossible for the vast majority of users. It is. But this is why threat modelling is important. If a realistic threat scenario is someone replacing your motherboard, then tpm2_totp should be something you setup. Listing all possible attack scenarios and assuming any generic distribution protect fully against them is a pipe dream. There needs to be some compromise between usability and security.

phh 5y ago

Now we're talking proper security, thanks. > Modern computers has tamper detection and if you open them you'll need to type the BIOS password. Is that somehow configurable from Linux distribution's setup, or it will require user to manually set a BIOS password? (and it requires the user to set a different bios password. if the user sets the same password for fde and for bios, then back to square 1) > However, replacing the motherboard is going to replace the TPM. This is easily detectable with something like tpm2_totp in the bootchain. That sounds interesting. Though it still sounds totally impossible for the vast majority of users. At that point, I don't really know what's the goal of TFA. If it's for extreme power users who want best security, it is missing the various counter-measures mentioned in this thread. If it's about pushing distributions to have better defaults, then I think it's quite moot, because secure boot won't improve security much to average users.

Foxboron 5y ago
>Is that somehow configurable from Linux distribution's setup, or it will require user to manually set a BIOS password? (and it requires the user to set a different bios password. if the user sets the same password for fde and for bios, then back to square 1) Not yet? And when I said "modern computers" i should probably clarify I'm thinking about more enterprise grade computers. Such as Thinkpads. Thinkpads also recently got the feature to set the password from Linux userspace. But I forget where I read that, and where the patch is located :) >That sounds interesting. Though it still sounds totally impossible for the vast majority of users. It is. But this is why threat modelling is important. If a realistic threat scenario is someone replacing your motherboard, then tpm2_totp should be something you setup. Listing all possible attack scenarios and assuming any generic distribution protect fully against them is a pipe dream. There needs to be some compromise between usability and security.