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Researchers Crack Open AMD's Server VM Encryption (theregister.co.uk)

Posted by msmash on from the security-woes dept.

Shaun Nichols, reporting for The Register: A group of German researchers have devised a method to thwart the VM security in AMD's server chips. Dubbed SEVered (PDF), the attack would potentially allow an attacker, or malicious admin who had access to the hypervisor, the ability to bypass AMD's Secure Encrypted Virtualization (SEV) protections.

The problem, say Fraunhofer AISEC researchers Mathias Morbitzer, Manuel Huber, Julian Horsch and Sascha Wessel, is that SEV, which is designed to isolate VMs from the prying eyes of the hypervisor, doesn't fully isolate and encrypt the VM data within the physical memory itself.

50 comments

  1. "malicious admin" by Joffy · · Score: 4, Insightful

    I feel like some of these stories are like Bob's Home Security fails to protect you if your wife is a serial killer.

    1. Re:"malicious admin" by Anonymous Coward · · Score: 3, Interesting

      Hey, Intel paid a lot of shekels for this very valuable research!

    2. Re:"malicious admin" by vux984 · · Score: 3, Insightful

      "I feel like some of these stories are like Bob's Home Security fails to protect you if your wife is a serial killer."

      To an extent they are, but if you are using cloud providers, the other tennants, and the monkeys at the cloud provider itself should all be considered potentially hostile.

      And even within companies there is this (legitimate) concept that everyone in IT shouldn't hold the keys to payroll, finance, HR, and the R&D trade secretes... so there are lots scenarios where the people administering the systems, the servers, the cloud fabric etc, shouldn't be able to get access to the contents of the virtual machines.

    3. Re: "malicious admin" by Anonymous Coward · · Score: 0

      Did these "researchers" give AMD advanced notification or just hand it over to the press the same day?

      If Intel spent more of their time and efforts on fixing 10 nm instead of looking for "flaws" in AMD's tech and having researchers present it as their own work they might get 10 nm out before 2020.

    4. Re:"malicious admin" by Anonymous Coward · · Score: 2, Interesting

      The old adage applies regardless: "He who has physical access, owns the data."

      It doesn't matter what it's running. If they have physical access, or local admin access, they own the data. All permissions derive from the admin account that set the system up in the first place. Trying to protect the system from the person who set it up / is responsible for maintaining it, is a fool's errand.

      The only reason we are having this discussion, is because everyone is too busy trying to save money by outsourcing the complexities and costs of IT to others while still trying to claim that they are the sole possessors of the data / processes. Nobody cares about the actual security, all they care about is the money. Well guess what? IT is a cost center. It doesn't make you money directly, but it is required to enable you to make money in a modern marketplace. You get from it exactly what you put into it. You don't wanna pay to manage your own IT? Don't expect the admin that's not under your control to abide by your desires. Sure you can have "agreements" and "contracts" with them, but remember this: Contracts and agreements only specify redress. They don't prevent a leak or malicious intent from happening in the first place. If your sole value in something is it's information. Then giving it to others should be the last thing on your mind. Especially if you are a service economy that doesn't produce enough to maintain itself if worse comes to worst and the info is copied without your consent by a competitor.

      TL;DR if you don't trust the person with permission to manage your IT with the data the IT contains, then you need to find someone you do trust to do it. Beyond that, the only assurance you have is the time it will take to copy it.

    5. Re:"malicious admin" by Anonymous Coward · · Score: 1

      but if you are using cloud providers, the other tennants, and the monkeys at the cloud provider itself should all be considered potentially hostile

      Um, yeah, but you considered them potentially hostile anyway. Nothing has changed. Except that maybe some snakeoil salesperson said that AMD's fancy new whatever would make it so that you could stop doing that, but you knew he was definitely lying, because it's impossible/impractical to hide software from the hardware it's running on.

      there are lots scenarios where the people administering the systems, the servers, the cloud fabric etc, shouldn't be able to get access to the contents of the virtual machines.

      Well, of course. When the snakeoil salesman says this bottle will cure your cancer, that seems like a good idea because there are lots of scenarios where you would prefer to not get cancer. But just because you want something, doesn't mean you can have it.

      Yes, there are scenarios where admins shouldn't have access to the VMs, but there aren't any scenarios where the admins don't have access to the VMs. They will definitely have it if they want it, and anyone who sells you a fix for that is making an extraordinary claim that requires extraordinary proof. Until they supply it, you just assume they are attempting to commit criminal fraud, to part you from your money by offering you an impossible dream thing that they are definitely not going to deliver.

    6. Re: "malicious admin" by Anonymous Coward · · Score: 0

      AMD can screw up without it being a conspiracy

    7. Re:"malicious admin" by TheRaven64 · · Score: 2

      The entire point of SEV (and Intel's SGX) is to protect the code against a malicious hypervisor. AMD tries to make a dubious distinction between a 'malicious' hypervisor and a 'compromised' hypervisor. Apparently they believe that if an attacker is able to run arbitrary code in the hypervisor, they are less of a threat than if they installed the same malicious code early on.

      That said, this is not news. There was a paper published at VEE a year ago (by the same researchers) showing how broken SEV is. Paolo Bonzini (KVM maintainer at Red Hat, among other things) was on the PC and pointed out that they had sent feedback to AMD prior to their shipping it pointing out that the design was fundamentally flawed. Apparently Microsoft sent similar feedback. AMD shipped it anyway, because they needed something to compete with SGX (which is less broken, but also a lot less general).

      --
      I am TheRaven on Soylent News
    8. Re: "malicious admin" by TheRaven64 · · Score: 1

      These researchers, Red Hat, and Microsoft all gave AMD feedback that SEV was broken and needed serious redesign before AMD shipped any products with SEV. This paper is just showing everyone that (some of) the attacks that were pointed out to AMD before they shipped the product actually work in practice.

      --
      I am TheRaven on Soylent News
    9. Re:"malicious admin" by Anonymous Coward · · Score: 0

      This is stupid. If someone has physical access to your machines, it's game over. There is no security that can stop them from getting at your information. If you want security you can't yield control of your systems to potentially hostile parties. It's that simple. At best encrypted data can safely be hosted on "the cloud." It's not secure if the remote machine is the one doing the encryption.

    10. Re:"malicious admin" by Anonymous Coward · · Score: 0

      Sure you can have "agreements" and "contracts" with them, but remember this: Contracts and agreements only specify redress.

      And the law even recognizes a concept called "efficient breach." That's where somebody can breach a contract when it's more beneficial to them to do so than to abide by the terms. For example, if your cloud provider's agreement says they won't sell your data, it doesn't mean they CAN'T sell you data. It just means they promise not to on pain of some penalty. If the penalty is less than they will make by breaching the contract, POOF! your data is gone.

    11. Re: "malicious admin" by Anonymous Coward · · Score: 0

      Just like your mom sells her ass. Please provide real cases of this childish theory. Everyone is an armchair lawyer. If theft of data is involved the civil penalties may be insignificant to getting raped in prison.

      You arm chair lawyers think civil and criminal are the same things. Just like small claims and district court. Fuck you.

  2. EPYC FAIL! by Anonymous Coward · · Score: 0

    Oh wow, another cutesy name: SEVered.

    Can we please stop giving vulnerabilities these over-the-top names and slogans?

  3. This is why you don't PAY for VM's by Anonymous Coward · · Score: 0

    This is exactly the reason you don't pay someone for your VM architecture. It's all insecure garbage... and this is igoring the fact that the NSA/BSA is deeply imbedded in evehing you do.. At least support the people that do it for free.

    1. Re:This is why you don't PAY for VM's by Anonymous Coward · · Score: 0

      Well no that's NOT exactly the reason. The server in your basement is going to have the same vulnerability as the one in the cloud.

    2. Re:This is why you don't PAY for VM's by duke_cheetah2003 · · Score: 1

      This is exactly the reason you don't pay someone for your VM architecture. It's all insecure garbage... and this is igoring the fact that the NSA/BSA is deeply imbedded in evehing you do.. At least support the people that do it for free.

      This is really bad advice. Hosted in your basement, or on someone elses data center, it really doesn't matter, you're vulnerable to attacks. All you can ever hope to do is mitigate the effects of any successful attack, and do everything you can to isolate things from each other, so an attacker has limited access and has to start anew to break into another isolated service.

      Economically, it doesn't even make dollar sense anymore to host internet servers in your basement. When one calculates the cost of owner ship, maintenance, support, etc, of having a physical server.. well, it just doesn't make sense. You can have the same thing in someone elses data center, without all the cost of ownership. You pay your bill, someone else deals with all the technicalities of keeping a computer up and running.

      Even an "insecure" data center hosted server can be hardened against attack, both externally and internally. The sheer volume of virtual machines running in a data center with literally 1000's of computers, all running VMs... yeah, unless you're some state intelligence agency, data center is good enough and secure enough. The levels of effort needs to FIND your VM, tamper with it in a way you're not going to know about. Who does this? And if was being done, why do you think just because you have the physical hardware in your basement, you're magically immune to attack? Silly.

      The bottom line, the one no one wants to admit to, or hear: You're not important enough for anyone to give a flying f about you or your server(s). If you were, you wouldn't be discussing it here on Slashdot. You'd have your own data center.

    3. Re:This is why you don't PAY for VM's by HiThere · · Score: 1

      If you really care about the security of your system, don't connect it to the net. Even indirectly.

      If you "sort of " care about the security of your system, only connect it indirectly. No direct web access. Use message passing of text messages to transfer info. It's not as fast, and it takes a bit more setup, but you can don anything that way that you can the other way.

      If you really don't care about security, put your data out on the cloud.

      --

      I think we've pushed this "anyone can grow up to be president" thing too far.
    4. Re: This is why you don't PAY for VM's by Anonymous Coward · · Score: 0

      I feel like there is room for inbetween solutions here.

    5. Re: This is why you don't PAY for VM's by HiThere · · Score: 1

      Yes. I should probably have put an ellipsis in between 'If you "sort of " care about..." and "If you really don't care about ...", because you're right, there are a very large number of intermediate positions. There are also a few intermediate positions between the first two positions. I guess I thought it was sufficiently obvious.

      For example, one intermediate position it to use a self-hosted web platform using only the http subset that existed before javascript. Or to host your system on a box that has a read-only drive. (Since we're talking intermediate positions we could distinguish between a read only drive and a normal drive that's mounted read only.) Etc.

      And there are degrees of security lower than a standard cloud platform, too.

      --

      I think we've pushed this "anyone can grow up to be president" thing too far.
    6. Re:This is why you don't PAY for VM's by Spamalope · · Score: 1

      The sheer volume of virtual machines running in a data center with literally 1000's of computers, all running VMs... yeah, unless you're some state intelligence agency, data center is good enough and secure enough.

      Sure... Script kiddies and ransomware must not exist in your world.

      6 figure plus targets means an automated attack. Do you think a ransomeware group cares if they destroy 999 VMs to get to 1 owner who pays? Manpower per payment is all that matters, and you're describing a huge group of vulnerable targets.

    7. Re:This is why you don't PAY for VM's by flux · · Score: 1

      However when you factor in a 1 Gbit or preferably 10 Gbit connection to said server for ie. having your / of your desktop computers there, the economics turn upside down.

      Hopefully that will change in the future.

    8. Re: This is why you don't PAY for VM's by Anonymous Coward · · Score: 0

      Difference is, I own and control that server in my basement and can fix it. I don't own that cloud server and I am at the mercy of my provider.

  4. Wait a minute... by Narcocide · · Score: 4, Insightful

    If you have access to the hypervisor you already have full control over the guests even without this "exploit." Why is this considered a big deal exactly?

    1. Re:Wait a minute... by Anonymous Coward · · Score: 1

      Hush you. Intel just got hit with a bunch of new bad bugs, you're ruining the distractive narrative! We're all supposed to look at AMD now.

    2. Re: Wait a minute... by Bing+Tsher+E · · Score: 1

      Is Intel vs. AMD part of the Marvel Universe yet? Because I have no problem ignoring all the superhero shit, and tis seems like the same kind of fanboy shit. Marvel! No, DC! No Intel! No no no! AMD!

      A bunch of comic book crap.

    3. Re:Wait a minute... by Anonymous Coward · · Score: 0

      Except if the hypervisor could be trusted in the past to provide a public key for which the hardware has a corresponding private key the hypervisor can't read but the SVE extension can, then you can in theory construct a VM which cannot be directly compromised but can at most be vulnerable to replay attacks or other indirect attacks (or simple disable the guest as a DoS). The "big deal" then is precisely that even further in the future AMD could sign public keys and hence even possibly get to the point of running VMs only wholly untrusted hypervisors.

      Because the current trend of cloud computing is going to collapse when it becomes clear the governments of the world are forcing/paying Amazon, Google, and Microsoft to grant them unrestricted access to user data. Sure, they could then further compromise AMD and get them to start signing public keys, but that's a bit more difficult to pull off and any sort of weakness in the algorithm is something that might well be detected by researchers, just like this exploits have been.

    4. Re: Wait a minute... by Anonymous Coward · · Score: 0

      Amd's security solution doesn't do what it says on the tin.

    5. Re: Wait a minute... by Anonymous Coward · · Score: 0

      Dude, I don't care about AMD or Intel as such, but it's pretty damned obvious, and it has been so for a very long time, that one of these companies have far more questionable ethics than the other.

      I've never heard of AMD resorting to criminal behaviour like bribing or or extorting manufacturers OEMS to simply not buy from competitors with a superior product. I can't say the same for Intel.

      As for the latest year of highly publicised bugs, there's more of the same pattern emerging; The bugs that has hit Intel are generally far worse with more severe implications and bigger impact. Yet if you read on them you easily get the impression that they are really not a problem, and even if so, AMD is no better. Which is wrong, at least so far. For the final nail in the coffin, you need to look no further than the whole CTS Labs saga, which was such an obvious hit job and had Intel markings all over it. For a pretty good summary and analysis of the whole thing just watch this.

      This "news piece" follows exactly the same pattern: Big hoopla about some supposedly catastrophic AMD flaw which in reality is pretty "meh" - "Bad admin can steal secrets!", who'd have thunk? - right on the heels of Intel getting caught with their pants down in a really bad way again.

      I'm not saying AMD is flawless, but IMNSHO this is a diversion. We are being manipulated and I will not tolerate it.

    6. Re:Wait a minute... by gweihir · · Score: 1

      Because people are stupid.

      --
      Most ACs are not even worth the keystrokes to insult them. Be generically insulted by this and ignored otherwise.
    7. Re: Wait a minute... by Anonymous Coward · · Score: 0

      CTS seems to be having the last laugh so far. AMD has yet to patch any of the flaws listed amdflaws.com

    8. Re:Wait a minute... by TheRaven64 · · Score: 1

      As I said above, because the entire point of SEV is that a malicious hypervisor can't tamper with a VM running in an SEV partition. Memory is encrypted, register contents are encrypted on context switch, and the VM can encrypt the contents of the disk and all network traffic itself. There are a number of flaws in the design that were pointed out to AMD (by this group of researchers, among others) before they shipped a product. AMD went ahead and shipped it anyway and, shockingly, it turns out that the attacks work.

      --
      I am TheRaven on Soylent News
    9. Re: Wait a minute... by TheRaven64 · · Score: 1

      The bugs that has hit Intel are generally far worse with more severe implications and bigger impact.

      Compare apples and oranges. AMD's SEV is intended as a competitor to SGX. There are some Spectre-related SGX attacks, but these can be fairly easily mitigated in software. In contrast, SEV is completely broken and the breakage is fundamental to the design, not a defect of implementation. Microsoft, Red Hat, and the group of researchers in TFA (and probably others) told AMD this well over a year ago before AMD shipped any SEV-enabled cores. AMD still shipped the feature and advertised it as secure.

      --
      I am TheRaven on Soylent News
    10. Re: Wait a minute... by Anonymous Coward · · Score: 0

      Wrong. And did you notice that they "reserved the right" to not update the page, even if things changed? It was a 100% smear job. Only idiots who actually want to believe the crap on that page to be true would be fooled by it.

    11. Re:Wait a minute... by Anonymous Coward · · Score: 0

      Even if you have the hypervisor, you still want to make it hard to get into the containers.

      Also AMD processors get used in the cloud. The big thing in cloud is making your VM secure from the cloud provider - and they control the hypervisor.

      This breaks that... potentially.

  5. Not possible! by Anonymous Coward · · Score: 0

    Only Intel CPUs have design flaws, AMD CPUs are perfect marvels of engineering and never had issues!

    Between this, meltdown, spectre, rowhammer and god knows how many others (including Intel ME and AMD PSP), it's becoming clear that none of this hardware is secure, and the software running on top of it isn't much better.

  6. Wait a minute...doing it right. by Ostracus · · Score: 1

    Consider it an incentive to not skimp on hypervisor programming.

    The problem, say Fraunhofer AISEC researchers Mathias Morbitzer, Manuel Huber, Julian Horsch and Sascha Wessel, is that SEV, which is designed to isolate VMs from the prying eyes of the hypervisor, doesn't fully isolate and encrypt the VM data within the physical memory itself.

    I wonder if that's because doing so would incur too much of a performance penalty?

    --
    Shai Schticks:"You don't make peace with friends, you make peace with enemies"
    1. Re:Wait a minute...doing it right. by Anonymous Coward · · Score: 0

      Ditto

    2. Re:Wait a minute...doing it right. by flux · · Score: 1

      The article ends with

      > "A low-cost efficient solution could be to securely combine the hash of the pageâ(TM)s content with the guest-assigned GPA."

    3. Re: Wait a minute...doing it right. by Anonymous Coward · · Score: 0

      I have 2.2 GPA you insensitive clod.

  7. Nice try by Anonymous Coward · · Score: 0

    Nice try. But I'm still not considering Intel CPUs for personal or business use anytime over the next several years.

    1. Re: Nice try by Bing+Tsher+E · · Score: 1

      It's virtuous, heroic and enlightened to pick another brand!

    2. Re: Nice try by HiThere · · Score: 1

      I'm not sure about "heroic", and I'd have added the adjective "selfish".

      --

      I think we've pushed this "anyone can grow up to be president" thing too far.
  8. No physical access by Anonymous Coward · · Score: 0

    But a pwned hypervisor. Right.

  9. what a bug... by Anonymous Coward · · Score: 0

    "malicious admin who had access to the hypervisor".. please dear researchers, go in the fields to peak up potatoes..

  10. The repetition is the enemy of the security. by Anonymous Coward · · Score: 0

    Try to encrypt pages full of zeros or full of efes: the encryption's keys maybe discovered.

    The encryption is also a performance penalty compared to no-encryption in hardware.

  11. Insecure by design by duke_cheetah2003 · · Score: 2

    All modern PC's were never designed with the thought in mind: There will be millions of attacks against this to try and break in.

    We just didn't think about that when we designed this stuff, which was before the internet really took off. Of course it's all insecure and broken, it wasn't designed to be hardened against the countless ways security researchers are finding into these designs.

    When the "forces that be" decide to scrap everything we've created upto now, and start anew, with a security focus right at the starting line, then we'd get some hardware and software platforms that're truly hardened against any attack.

    Bandaids over the x86 paradigm? Waste of time. It's never going to be secure, not against everything everytime. It's just not designed to be secure, we didn't think it needed to be. We didn't think there'd be millions of malicious actors in the wild, with our computers all interconnected by the internet, so everything is exposed to everyone. We just didn't think that'd ever happen. It shows.

    1. Re:Insecure by design by Anonymous Coward · · Score: 0

      Too bad when that eventually happens, every machine (and the internet) will be locked down tighter than an NSA mainframe and you will be under surveillance 24/7.

  12. This is patchable by Anonymous Coward · · Score: 0

    It should be fairly straightforward to implement a solution which programs the IOMMU in AMD systems to prevent malicious actors from futzing with the hypervisor's page tables. It still requires some root of trust though, as do most solutions for these types of problems. At least it using the IOMMU for protection should take third party drivers out of the equation.

  13. The hypervisor can see anything by gweihir · · Score: 1

    There is not really a way around this and there are numerous ways to bypass any protection mechanism. This is hardly news, except to the clueless that believe the marketing hype.

    --
    Most ACs are not even worth the keystrokes to insult them. Be generically insulted by this and ignored otherwise.
  14. Sounds good!! by Anonymous Coward · · Score: 0

    Sounds great.
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