Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

faulTPM: Exposing AMD fTPMs' Deepest Secrets

arxiv.org

Post reply on HN
Print view View original

41–50 of 273 posts

Re: faulTPM: Exposing AMD fTPMs' Deepest Secrets

#41

Post by tester756 »

doubled112 wrote: post #32
r2_pilot wrote: post #19

Earlier quoted context omitted.

Microsoft is edging closer and closer to dropping support for Windows 10(even a computer I built in 2017 that's still running perfectly fine can't upgrade). But for many users, changing to another OS besides Windows is tantamount to not functioning, so planned obsolescence continues apace.

I did find it odd that my Ryzen 7 1700X (8 cores, 16 threads, 3.4GHz) was suddenly "not good enough" to run the OS.

Isn't this about Spectre/Meltdown vulns instead of the perf. specs?

Re: faulTPM: Exposing AMD fTPMs' Deepest Secrets

#44

Post by bo1024 »

cwerling wrote: post #18
aceazzameen wrote: post #3

It says any TPM can be defeated in 2-3 hrs with physical access. Is the AMD one different? Can it be defeated over networks? And is this something I should be concerned about since I just bought a new AMD machine?

One of the authors here. This attack is relevant if your machine is physically exposed to attacks, e.g., in an office environment or while traveling, and if you don't use any additional pre-boot passphrase to protect the disk (but rely solely on AMD's fTPM). When TPMs became popular, dedicated TPMs were mainly used, being a separate chip on the mainboard connected via the SPI or LPC bus. These were prone to (relative…

This is important because one purpose of TPMs is to prevent the owner of the machine from doing certain things (as in Digital Rights Management). And the owner of the machine presumably has physical access.

Re: faulTPM: Exposing AMD fTPMs' Deepest Secrets

#46

Post by dathinab »

bo1024 wrote: post #44
cwerling wrote: post #18

Earlier quoted context omitted.

One of the authors here. This attack is relevant if your machine is physically exposed to attacks, e.g., in an office environment or while traveling, and if you don't use any additional pre-boot passphrase to protect the disk (but rely solely on AMD's fTPM). When TPMs became popular, dedicated TPMs were mainly used, being a separate chip on the mainboard connected via the SPI or LPC bus. These were prone to (relative…

This is important because one purpose of TPMs is to prevent the owner of the machine from doing certain things (as in Digital Rights Management). And the owner of the machine presumably has physical access.

no

they are for boot chain security which is an essential featur for any laptop

TPM by itself never prevents anyone from doing anything

but it's used with features like secure boot, but as long as they fully implement the spec they don't prevent you from doing with your laptop what you want as long as you don't install software which does so

secure enclave and similar used for DRM isn't directly a TPM feature but more an extension using TPM and other CPU features

and yes it can be used to security store keys in your hardware. Any keys! A feature any user understanding security would appreciate.

Re: faulTPM: Exposing AMD fTPMs' Deepest Secrets

#47

Post by jeroenhd »

doubled112 wrote: post #32
r2_pilot wrote: post #19

Earlier quoted context omitted.

Microsoft is edging closer and closer to dropping support for Windows 10(even a computer I built in 2017 that's still running perfectly fine can't upgrade). But for many users, changing to another OS besides Windows is tantamount to not functioning, so planned obsolescence continues apace.

I did find it odd that my Ryzen 7 1700X (8 cores, 16 threads, 3.4GHz) was suddenly "not good enough" to run the OS.

It'll work fine, Microsoft even explains how to upgrade: https://support.microsoft.com/en-us/windows/installing-windo...

They chose an arbitrary cut-off date for hardware support for their new OS. They decided not to support old stuff anymore and they had to pick a date/technology platform. It was always going to be arbitrary. In my opinion they should've picked a clearer distinction (i.e. require a certain level of AVX support so all binaries can be built with AVX optimizations enabled) but I can see why they chose to do this. After all, they're going to have to support the OS for ten years, that four year old CPU is fourteen years old by the time Windows 11 goes out of support.

Re: faulTPM: Exposing AMD fTPMs' Deepest Secrets

#48

Post by dfox »

goolz wrote: post #16
smarx007 wrote: post #10

Earlier quoted context omitted.

Yes, relevant in case of a lost device: "Motivated by Windows 11’s push to use the TPM for even more applications, we apply the vulnerability to Microsoft BitLocker and show the first fTPM-based attack against the popular Full Disk Encryption solution. BitLocker’s default TPM-only strategy manages – without any changes to the user experience – to swiftly step up a user’s security in the face of a lost or stolen devic…

Does this line imply then it is mostly a concern for Windows users? I don't mind only using Linux, it is Best in Slot for most tasks anyways.

Typical Linux installation will not rely on TPM in any way. But if you use systemd-cryptenroll to provide BitLocker-like UX for FDE then the concerns are mostly same.

Re: faulTPM: Exposing AMD fTPMs' Deepest Secrets

#49

Post by bootsmann »

jeroenhd wrote: post #34

Gnarly, especially because these vulnerabilities seem unpatchable. Luckily, it seems TPM+PIN should remain safe if your PIN is difficult enough to brute-force, though. As this includes an attack against the secure processor, does this also pose risks to any DRM keys?

PIN needs to be quite long (and most certainly alphanumeric) for this to work, see the table in 5.3.1

Re: faulTPM: Exposing AMD fTPMs' Deepest Secrets

#50

Post by reisse »

r2_pilot wrote: post #19
judge2020 wrote: post #14

Earlier quoted context omitted.

> Every time I think about the millions of computers that will be declared worthless this year, it makes me a little bit more angrier. What is this a reference to? Every computer I've found will let you boot into the bios and disable secure boot or add new keys to the trust store.

Microsoft is edging closer and closer to dropping support for Windows 10(even a computer I built in 2017 that's still running perfectly fine can't upgrade). But for many users, changing to another OS besides Windows is tantamount to not functioning, so planned obsolescence continues apace.

Dropping support, so what?

That does not make these PCs obsolescent in any way. People still use Windows 7, and even Windows XP. Especially in the many contexts where "security" is not important at all.

Post reply on HN