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When Lightning Strikes Thrice: Breaking Thunderbolt 3 Security

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Re: When Lightning Strikes Thrice: Breaking Thunderbolt 3 Security

#81

Post by redactions »

osy wrote: post #23

This is the kind of garbage that the infosec community often memes about. A marketing website, a domain name, a cute logo for a vanity project masquerading as security research. Basically every one of the "seven" vulnerabilities boils down to "if someone can flash the SPI of the thunderbolt controller then xxx" but if they can flash the TB SPI, then they can also flash the BIOS SPI which has a lot of the same "vulner…

Have you documented or published any of your Thunderbolt reverse engineering efforts?

Re: When Lightning Strikes Thrice: Breaking Thunderbolt 3 Security

#82

Post by mjg59 »

znpy wrote: post #57
mjg59 wrote: post #49

Earlier quoted context omitted.

An example is using glitter-containing nail polish to cover the screws, taking a high resolution picture and then having an app that checks whether the glitter particles are still in the same position. There are companies selling solutions along these lines.

First things first: lol. After that: at this point it's easier to pay a random person to follow you and steal your whole bag/backpack and wallet and make it look like the usual theft. Or just break into your house/office or whatever.

The point is that even having physical possession of the system shouldn't be enough to get anything useful out of it.

Re: When Lightning Strikes Thrice: Breaking Thunderbolt 3 Security

#83

Post by tptacek »

redactions wrote: post #79
tptacek wrote: post #15

Earlier quoted context omitted.

Because they need to open up the victim's device to read its TB3 configuration directly off the SPI flash that holds it; that's how they get the malicious device to work in the first place.

Many smaller devices do not require tools and are trivial to clone. Any of the victim devices will do. It's not only useful to attack a target computer. Device identifiers and capabilities are not bound to the security level secret values. Drop off a pre-cloned video adapter in a conference room. If it is used and as a result authorized by a targeted computer at a later moment in time, it's game over. An attacker may…

You almost certainly know more about this than me, but hasn't macOS been breaking this attack --- malicious PCIE DMA --- for several years now with its IOMMU configuration? Ivan Krstic has a whole series of BH slides about this, and in the context of T2.

The point about attacking trusted devices and pre-cloning devices is well taken.

Re: When Lightning Strikes Thrice: Breaking Thunderbolt 3 Security

#84

Post by tptacek »

mjg59 wrote: post #82
znpy wrote: post #57

Earlier quoted context omitted.

First things first: lol. After that: at this point it's easier to pay a random person to follow you and steal your whole bag/backpack and wallet and make it look like the usual theft. Or just break into your house/office or whatever.

The point is that even having physical possession of the system shouldn't be enough to get anything useful out of it.

Our phones are just small computers, and the notion that the FBI can get things out of them given permanent custody is national news. It's weird that people think this isn't really one of the battle lines in computer security.

Re: When Lightning Strikes Thrice: Breaking Thunderbolt 3 Security

#85

Post by pvg »

znpy wrote: post #57
mjg59 wrote: post #49

Earlier quoted context omitted.

An example is using glitter-containing nail polish to cover the screws, taking a high resolution picture and then having an app that checks whether the glitter particles are still in the same position. There are companies selling solutions along these lines.

First things first: lol. After that: at this point it's easier to pay a random person to follow you and steal your whole bag/backpack and wallet and make it look like the usual theft. Or just break into your house/office or whatever.

You lol but a similar scheme was used for nuclear weapons treaty compliance verification (search for 'epoxy'):

https://www.washingtonpost.com/archive/politics/1988/03/21/a...

Re: When Lightning Strikes Thrice: Breaking Thunderbolt 3 Security

#86

Post by zokier »

redactions wrote: post #76
zokier wrote: post #69

Earlier quoted context omitted.

That is exactly what TB has. The problem is that the device private key (in many(/all?) devices) sits in the flash memory completely unprotected so anyone can clone it.

It is not like ssh at all. It is a problem that secrets are kept in the flash and it is also a problem that those secrets are sent over the untrusted channel.

The key is transferred only on the initial connection, after that a challenge/response mechanism is used. So from UX point of view it achieves similar TOFU, even if the technical details vary a bit. Sure, its bit worse but it is still very much trust on first use.

Re: When Lightning Strikes Thrice: Breaking Thunderbolt 3 Security

#87

Post by AnthonyMouse »

mjg59 wrote: post #54
AnthonyMouse wrote: post #52

Earlier quoted context omitted.

I guess at that point you're basically asking whether it's possible to make higher resolution printers than cameras, but considering you can in principle do printing using lithography similar to what they use to make semiconductors, that's probably going to win over the average phone camera. Although you're obviously then talking about a much more sophisticated attack.

It's not just a matter of printing, it's a matter of placement. If you can carry equipment of that calibre into a hotel room and do the swap then that'll defeat things, but it's not clear that that's realistic.

You wouldn't necessary need it to be in the hotel room. You sneak in, take a picture, have the lab down the street reproduce it, come back in a half hour and make the swap.

That's also assuming you would actually need that level of sophistication. It's plausible that there is a level of printing technology somewhere between "crappy inkjet" and "semiconductor fab clean room" that could still fool a phone camera.

There is also the possibility of accessing the inside of the machine without tearing the sticker. You think they're going to disassemble it by removing the screws, but they actually disassemble it by slicing off a section of the case with a sharp blade and then epoxying it back together. Or make their modifications through the cooling vents.

And that's really the other problem too. If you don't know how they're going to do it, you don't know what to look for to detect that they did. Your sticker is intact so you're safe, right? Right?

Re: When Lightning Strikes Thrice: Breaking Thunderbolt 3 Security

#88

Post by oicat »

There is a nice write-up about this on attackerkb. If you're not familiar with it it's a community to provide assessments of vulnerabilities and point out which are worth stopping everything to patch and which are mostly harmless. It's currently in open beta. Main site: https://attackerkb.com/ Thunderspy assessment: https://attackerkb.com/topics/mPaHZgsUvk/thunderspy

Re: When Lightning Strikes Thrice: Breaking Thunderbolt 3 Security

#89

Post by mjg59 »

AnthonyMouse wrote: post #87
mjg59 wrote: post #54

Earlier quoted context omitted.

It's not just a matter of printing, it's a matter of placement. If you can carry equipment of that calibre into a hotel room and do the swap then that'll defeat things, but it's not clear that that's realistic.

You wouldn't necessary need it to be in the hotel room. You sneak in, take a picture, have the lab down the street reproduce it, come back in a half hour and make the swap. That's also assuming you would actually need that level of sophistication. It's plausible that there is a level of printing technology somewhere between "crappy inkjet" and "semiconductor fab clean room" that could still fool a phone camera. There…

You're still left with needing perfect placement, which isn't something that's realistic to do by hand. Physical case modifications are also going to be detected by any reasonable tooling (there's at least one vendor who can tell you which physical mold something came off on the production line via phone camera imaging, they're definitely going to spot a glued together hole in the case). So you're left with going in via existing case holes as the most realistic option, which has raised the bar by a significant amount - this is now an attack that's going to take much longer and require a higher level of skill, so the probability that it'll be carried out is reduced by a lot.

Nobody is realistically going to say that a computer plugged into the internet is unhackable. Instead the goal is to make it sufficiently difficult to hack that it's either cheaper to solve the problem a different way or target a different person. The same is true here. Nobody believes it's literally impossible to compromise an iPhone when you have physical access, but it's considered hard enough that almost any other option is preferable. We should be holding laptops to the same standard.

Re: When Lightning Strikes Thrice: Breaking Thunderbolt 3 Security

#90

Post by xoa »

AshamedCaptain wrote: post #70
mappu wrote: post #16

Earlier quoted context omitted.

> if an attacker has unencumbered access to one’s device, all security goes flying out the window This is rapidly starting to become less true - full disk encryption is everywhere, backed by hardware TPMs; the Lockdown LSM prevents root from owing the boot chain; devices with soldered RAM are functionally immune to cold boot attacks. There are still things an attacker can do - put a hardware keylogger on the keyboard…

Full disk encryption is still be broken, given a decade or 3. You might care about that risk or not, but the fact is still there. The point still is that if the attacker has unencumbered access to your device then indeed _further_ use of the device is unrecommended to say the least. It doesn't matter if you had or did not have full disk encryption. It does not matter if you had or did not have Thunderbolt. An extreme…

> Full disk encryption is still be broken, given a decade or 3.

What? FDE is all symmetric crypto, long since 256-bit, and I think all AES. AES is extremely well understood, and the threat scenario for FDE is also purely cold attacks so even any side channels are irrelevant. I've never seen any feasible attack suggested even in principle, so I'm curious what you have in mind in 10-30 years. If you're thinking "quantum computers", you've gotten confused. Against symmetric keys those only provide at best square root(n) speed up via Grover's Algorithm, essentially halving the key size space. But 128-bit is still infeasible to search, and it'd be trivial to counter anyway by doubling the key length. It's only against current asymmetric cryptosystems that Shor's Algorithm can apply in principle (if if Big-If an actual scalable general purpose QC can actually be built).

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