6 ms·

At first it looks nice "oh now we can get rid of it" but it also opens up a very scary near future security-wise. We've now entered a realm where an attacker c

by nolok 9y ago

At first it looks nice "oh now we can get rid of it" but it also opens up a very scary near future security-wise. We've now entered a realm where an attacker could simply plug a device on an usb port of your computer for a few seconds to have it access your cpu's ME through USB JTAG and take over it, allowing him to have full access and control over what you do/read/open/type over the network, without you ever knowing it since you can't see it. And the only way to get rid of it for sure would be to pretty much throw that cpu away and buy a new one. Or am I being overly paranoid and there is something I haven't considered that makes this scenario impossible ? EDIT: given the answers I think my main concern wasn't well expressed above. I'm not saying this as in "ME is making it easier to be compromised". That may or may not be true, but that's not my point. My point is, we all know that once compromised, you can't clean it and need to burn it all and start from scratch: recover from backup (not files on the compromised machine), format everything, reinstall. Due to the nature of the ME, this is not a solution here. The cleanup needs to be done at the hardware level. Unless I misunderstood something, once it happens, your cpu is done for, period. And 'using a hack to cleanup the hack' is still in the realm of cleaning up rather than start from scratch, it's not a solution for the same reason than cleaning up your comprised linux box is not one and you need to start from scratch.

maccard 9y ago
I think you're being overly paranoid. If the attacker has physical access to the machine, chances are you're compromised anyway, even before this vulnerability.
- vog 9y ago
  I wonder how long it will take until an attack over the network is found.
  - turblety 9y ago
    You mean another one? [1] 1. https://thehackernews.com/2017/05/intel-amt-vulnerability.html https://thehackernews.com/2017/05/intel-amt-vulnerability.ht...
- richmarr 9y ago
  So you're saying things are so bad anyway that this one vulnerability probably doesn't make any difference? This interpretation of "you're being overly paranoid" is new to me ;)
  - sametmax 9y ago
    Come on, you can already catch aids, why do you worry about cancer ?
- breakingcups 9y ago
  I don't think thats the right attitude. There's a difference between being able to open a machine to install malicious hardware / steal hdd's or just plugging in a generic USB stick to pawn it. I know some of you might argue that even generic USB sticks can do damage and, whilst I agree, this attack is still a degree worse than most of those. Thus far the most damage an unknown USB stick could do was type commands as a fake keyboard (visible to user) or exploit a driver vulnerability to silently cause mischief. Correct me if I'm wrong, but those cases could still be trivially stopped by a security policy set by administrators disallowing unknown USB devices. (Of course, how many places would use this is another matter, but it's still very important for places where this does matter.) This attack on the other hand would seem to be able to completely bypass your operating systems restrictions on USB ports.
  - fragmede 9y ago
    From a technical perspective there is a difference now that this is public, but from a security stance, physical access is physical access. Why? Security knows there are always bugs in software, and assumes they exist. Thanks to @h0t_max, the rest of us know this particular bug exists, but this bug has been around for a while - who's to say evil hax0rs didn't find this bug years ago and have been exploiting it since? Or put another way - you say an unknown USB stick could exploit a driver vulnerability to silently cause mischief, and then claim that this is easily stopped if an administrator sets a security policy to disallow unknown USB devices. (I assume you mean a Windows GPO enforced policy or similar, and not a written social policy.) Who's to say the code that enforces the policy doesn't have bugs that's exploitable? What if the driver for a known USB stick has exploits? Physical access is physical access, and while there are mitigations for the evil maid attack (like an encrypted drive and shutting down -not just suspending, when the machine is out of sight), there simply is no way around the fact that physical access is game over.
    - cyphar 9y ago
      > while there are mitigations for the evil maid attack (like an encrypted drive and shutting down -not just suspending, when the machine is out of sight), That mitigation is useless against Evil Maid. There are much more sophisticated mitigations (using a TPM to measure the boot, and then do something akin to TOTP in order to allow the user to actually verify the state of the machine) which actually could protect against Evil Maid almost completely (assuming you don't have something like Intel ME that cannot be verified by the TPM). "Once you have physical access it's game over" is a very common response to these discussions, and I find it incredibly defeatist. Of course physical access means that the "clock is ticking" until your data is compromised, but sufficient protections can dampen the impact or increase the difficulty. For example: IOMMU protects against DMA-based attacks, something that was impossible to protect against several years ago. This doesn't mean that someone cannot launch other attacks, but it does mean that the trivial "just plug anything into a USB port and you have DMA" attack is no longer possible.
- nolok 9y ago
  As I said above; I think I didn't make my point clear enough: my concern was not about it making it easier to be comprised, but about it making the clean up pretty impossible, on a hardware level. Software do-over is a very well accepted solution (don't bother cleaning the rootkit, just format reinstall), but hardware do-over (change the cpu) is going to be a hard pill to swallow.
  - cyphar 9y ago
    This was a problem even before Intel ME. Modern server motherboards (and several workstations) have a second Linux installation on your motherboard (known as a "baseboard management controller" or BMC) that cannot be removed. There have been many exploits found in the software running on BMCs, and if you want to "clean up" an infected server then you have to throw out the hardware if you want to be 100% certain.
    - shenki0 9y ago
      The bmc situation is changing. There's an effort to support the ARM SoCs upstream, and there are a number of companies working on open source BMC stacks. https://github.com/openbmc https://github.com/openbmc
- sametmax 9y ago
  For now. You need a first step before the next. I'm waiting for them to own ME remotely now. It's unlikely they won't succeed.
- gaius 9y ago
  If the attacker has physical access to the machine, chances are you're compromised anyway, even before this vulnerability Can you not see the difference between an attacker opening the case and stealing your HD, vs inserting USB key for a few seconds, then going away, and exploiting later at their leisure?
vog 9y ago
It's by far not the first time that a highly-priviledged "security" component turns out to actually reduce security, because it is a large and gainful attack surface. I can't help but to think of all those exploits that target anti-virus software.
- gargravarr 9y ago
  "I know, let's examine some suspicious code in a highly-privileged process that the user explicitly trusts to keep them safe." When you think about it, "it seemed like a good idea at the time" can explain most tragedies in human histories.
  - zAy0LfpBZLC8mAC 9y ago
    Except it never seemed like a good idea to anyone with a clue of IT security.
  - sametmax 9y ago
    Well, a few hours ago we had a thread on HN about eradicating a whole specy of insects. And we had in comments intelligent educated people that though that "it seems like a good idea". So if mass disruption of the very system that support your life can have supporters among a community composed of smart and actively debating people, "it seemed like a good idea at the time" probably happens every week at gov agencies.
    - Kadin 9y ago
      Lots of things are done because there's a broad consensus opinion that it's a good idea. There is nothing intrinsically bad about that, and needless or baseless skepticism is often counterproductive and paralyzing, leading to inaction even in the face of widespread consensus. What leads to failures, and I suspect happened at Intel, was that they mistook a very localized consensus for a broader one. There's a word for this, it's called "groupthink". A group of people can talk themselves into doing something very stupid (or evil) while still thinking they're doing the right thing, given enough time and motivation. There was no widespread consensus, outside of Intel, that the IME was a good idea. If they had solicited opinions from outside their organization, they would doubtless have gotten horrified reactions. But they didn't, or if they did they must have dismissed those concerns, because they went through with the bad idea anyway. The apparent secrecy with which they developed the IME is also a cause for alarm; groups of people who operate in isolation are particularly prone to groupthink, and so even if their motivations are good ones, the fact that they are working without continuous feedback from anyone on the outside raises the chances of a perverse outcome.
gargravarr 9y ago
The 'evil maid' attack is well known, and states that once someone has physical access to your computer, all bets are off. Anything that has DMA enabled (e.g. Firewire or Thunderbolt) offers an external device direct access to the system RAM that is very difficult to defend against, or they could attach a keylogger or modify your bootloader, basically unleash all manner of havok. USB JTAG is really no different from a security POV. The concern with the Intel ME is that it has a native network adapter. You can bet efforts are currently underway to discover how to exploit the ME remotely. THAT'S when things get scary. Your paranoia is not unjustified. Personally, I am nervous that some of my systems have the ME. When attention turned to it about a year ago, i knew it would only be a matter of time before someone broke into it.
- deleted 9y ago
  [deleted]
- cyphar 9y ago
  > Anything that has DMA enabled (e.g. Firewire or Thunderbolt) offers an external device direct access to the system RAM that is very difficult to defend against IOMMU effectively solves the "DMA is completely broken" problem, as far as I'm aware. Evil Maid attacks are mostly worrisome because even UEFI cannot protect you against some bootloader attacks (what if you disable UEFI or reflash the firmware and then have a bootloader that just looks like a UEFI boot). There are some usages of TPMs that seem quite promising (they revolve around doing a reverse-TOTP-style verification of your laptop to ensure that the TPM has certified the entire boot chain). It's quite a hard problem, made significantly harder by the fact that every fucking hardware vendor seems to want to make our machines even less secure.
  - gargravarr 9y ago
    The problem is hard mostly because the entire architecture of the personal computer made absolutely no provision for security. Everything is patches upon patches to add superficial security. Fundamentally, a computer is dumb, it will perform whatever task it is told to do, and all our security measures revolve around stopping a malicious actor from telling the computer to do something 'bad'. Eventually, someone gets around the bouncer or in through an open window and here we are.
cryogenic_soul 9y ago
Many people will now start to dig in. War is started and I hope somebody will find a way to totally remove/replace(with a stub) Intel ME before some critical vulnerability will be discovered in the Intel ME's network stack. In white hats we trust :)
- gargravarr 9y ago
  Here's hoping. Intel did a great job hiding the thing and making it all but impossible to remove (at present if you nuke the firmware, the CPU will totally fail to initialise. Thanks Intel!). That said, we're talking about an embedded device with very low-level code, and any 'disabling' code is probably going to be distributed in binary form. Stands to reason somewhere along the lines, someone is going to turn that around for their own benefit. In tin-foil hats, we trust, more like!
  - arca_vorago 9y ago
    I just get tired of being ridiculed and then 10 years later vindicated. In Faraday cages we trust.
    - gargravarr 9y ago
      2013 was the greatest 'WE TOLD YOU SO' in history for the tin-foil-hat brigade...
      - raverbashing 9y ago
        Why 2013 specifically?
        cyphar 9y ago
        Presumably because of https://en.wikipedia.org/wiki/Edward_Snowden#Publication https://en.wikipedia.org/wiki/Edward_Snowden#Publication
tinus_hn 9y ago
The vulnerability exists, wether someone reveals it to the public or not. These people found it with Intel keeping the working of the system under wraps as much as possible. You can imagine the kind of access available to people who did get to see the source code. At least now that everyone can see the problem people can make informed decisions.
- goldenkey 9y ago
  I would think those people are under constant threat of being kidnapped for their information
  - sametmax 9y ago
    Given the complexity of the thing, they need a LOT of high profile people to create such a stuff. It's very unlikely none of them have been either: - bribed - threaten - felt guilty about it and decided to make amend My money is that exploits have been on the blacks market for a while now. We just have an official public demo now. Rule of thumb: when something that catastrophic is made public, the worst already happened and you are late to the party.
blhack 9y ago
Is it still true that USB devices can be used to execute code on a target's system without user interaction? I thought this behavior disappeared ~10 years ago.
- IshKebab 9y ago
  They shouldn't be able to. Firewire devices can because they used DMA without memory protection. I don't think Thunderbolt has the same flaw. However there are bugs in USB stacks, especially now you can do so many alternate protocols over USB-C. https://www.jefftk.com/p/malicious-usb-sticks https://www.jefftk.com/p/malicious-usb-sticks There's nothing fundamental in the USB spec that lets devices execute code on the host.

by nolok 9y ago

maccard 9y ago

I think you're being overly paranoid. If the attacker has physical access to the machine, chances are you're compromised anyway, even before this vulnerability.

vog 9y ago
I wonder how long it will take until an attack over the network is found.
- turblety 9y ago
  You mean another one? [1] 1. https://thehackernews.com/2017/05/intel-amt-vulnerability.html https://thehackernews.com/2017/05/intel-amt-vulnerability.ht...
richmarr 9y ago
So you're saying things are so bad anyway that this one vulnerability probably doesn't make any difference? This interpretation of "you're being overly paranoid" is new to me ;)
- sametmax 9y ago
  Come on, you can already catch aids, why do you worry about cancer ?
breakingcups 9y ago
I don't think thats the right attitude. There's a difference between being able to open a machine to install malicious hardware / steal hdd's or just plugging in a generic USB stick to pawn it. I know some of you might argue that even generic USB sticks can do damage and, whilst I agree, this attack is still a degree worse than most of those. Thus far the most damage an unknown USB stick could do was type commands as a fake keyboard (visible to user) or exploit a driver vulnerability to silently cause mischief. Correct me if I'm wrong, but those cases could still be trivially stopped by a security policy set by administrators disallowing unknown USB devices. (Of course, how many places would use this is another matter, but it's still very important for places where this does matter.) This attack on the other hand would seem to be able to completely bypass your operating systems restrictions on USB ports.
- fragmede 9y ago
  From a technical perspective there is a difference now that this is public, but from a security stance, physical access is physical access. Why? Security knows there are always bugs in software, and assumes they exist. Thanks to @h0t_max, the rest of us know this particular bug exists, but this bug has been around for a while - who's to say evil hax0rs didn't find this bug years ago and have been exploiting it since? Or put another way - you say an unknown USB stick could exploit a driver vulnerability to silently cause mischief, and then claim that this is easily stopped if an administrator sets a security policy to disallow unknown USB devices. (I assume you mean a Windows GPO enforced policy or similar, and not a written social policy.) Who's to say the code that enforces the policy doesn't have bugs that's exploitable? What if the driver for a known USB stick has exploits? Physical access is physical access, and while there are mitigations for the evil maid attack (like an encrypted drive and shutting down -not just suspending, when the machine is out of sight), there simply is no way around the fact that physical access is game over.
  - cyphar 9y ago
    > while there are mitigations for the evil maid attack (like an encrypted drive and shutting down -not just suspending, when the machine is out of sight), That mitigation is useless against Evil Maid. There are much more sophisticated mitigations (using a TPM to measure the boot, and then do something akin to TOTP in order to allow the user to actually verify the state of the machine) which actually could protect against Evil Maid almost completely (assuming you don't have something like Intel ME that cannot be verified by the TPM). "Once you have physical access it's game over" is a very common response to these discussions, and I find it incredibly defeatist. Of course physical access means that the "clock is ticking" until your data is compromised, but sufficient protections can dampen the impact or increase the difficulty. For example: IOMMU protects against DMA-based attacks, something that was impossible to protect against several years ago. This doesn't mean that someone cannot launch other attacks, but it does mean that the trivial "just plug anything into a USB port and you have DMA" attack is no longer possible.
nolok 9y ago
As I said above; I think I didn't make my point clear enough: my concern was not about it making it easier to be comprised, but about it making the clean up pretty impossible, on a hardware level. Software do-over is a very well accepted solution (don't bother cleaning the rootkit, just format reinstall), but hardware do-over (change the cpu) is going to be a hard pill to swallow.
- cyphar 9y ago
  This was a problem even before Intel ME. Modern server motherboards (and several workstations) have a second Linux installation on your motherboard (known as a "baseboard management controller" or BMC) that cannot be removed. There have been many exploits found in the software running on BMCs, and if you want to "clean up" an infected server then you have to throw out the hardware if you want to be 100% certain.
  - shenki0 9y ago
    The bmc situation is changing. There's an effort to support the ARM SoCs upstream, and there are a number of companies working on open source BMC stacks. https://github.com/openbmc https://github.com/openbmc
sametmax 9y ago
For now. You need a first step before the next. I'm waiting for them to own ME remotely now. It's unlikely they won't succeed.
gaius 9y ago
If the attacker has physical access to the machine, chances are you're compromised anyway, even before this vulnerability Can you not see the difference between an attacker opening the case and stealing your HD, vs inserting USB key for a few seconds, then going away, and exploiting later at their leisure?

vog 9y ago

It's by far not the first time that a highly-priviledged "security" component turns out to actually reduce security, because it is a large and gainful attack surface. I can't help but to think of all those exploits that target anti-virus software.

gargravarr 9y ago
"I know, let's examine some suspicious code in a highly-privileged process that the user explicitly trusts to keep them safe." When you think about it, "it seemed like a good idea at the time" can explain most tragedies in human histories.
- zAy0LfpBZLC8mAC 9y ago
  Except it never seemed like a good idea to anyone with a clue of IT security.
- sametmax 9y ago
  Well, a few hours ago we had a thread on HN about eradicating a whole specy of insects. And we had in comments intelligent educated people that though that "it seems like a good idea". So if mass disruption of the very system that support your life can have supporters among a community composed of smart and actively debating people, "it seemed like a good idea at the time" probably happens every week at gov agencies.
  - Kadin 9y ago
    Lots of things are done because there's a broad consensus opinion that it's a good idea. There is nothing intrinsically bad about that, and needless or baseless skepticism is often counterproductive and paralyzing, leading to inaction even in the face of widespread consensus. What leads to failures, and I suspect happened at Intel, was that they mistook a very localized consensus for a broader one. There's a word for this, it's called "groupthink". A group of people can talk themselves into doing something very stupid (or evil) while still thinking they're doing the right thing, given enough time and motivation. There was no widespread consensus, outside of Intel, that the IME was a good idea. If they had solicited opinions from outside their organization, they would doubtless have gotten horrified reactions. But they didn't, or if they did they must have dismissed those concerns, because they went through with the bad idea anyway. The apparent secrecy with which they developed the IME is also a cause for alarm; groups of people who operate in isolation are particularly prone to groupthink, and so even if their motivations are good ones, the fact that they are working without continuous feedback from anyone on the outside raises the chances of a perverse outcome.

gargravarr 9y ago

The 'evil maid' attack is well known, and states that once someone has physical access to your computer, all bets are off. Anything that has DMA enabled (e.g. Firewire or Thunderbolt) offers an external device direct access to the system RAM that is very difficult to defend against, or they could attach a keylogger or modify your bootloader, basically unleash all manner of havok. USB JTAG is really no different from a security POV. The concern with the Intel ME is that it has a native network adapter. You can bet efforts are currently underway to discover how to exploit the ME remotely. THAT'S when things get scary. Your paranoia is not unjustified. Personally, I am nervous that some of my systems have the ME. When attention turned to it about a year ago, i knew it would only be a matter of time before someone broke into it.

deleted 9y ago
[deleted]
cyphar 9y ago
> Anything that has DMA enabled (e.g. Firewire or Thunderbolt) offers an external device direct access to the system RAM that is very difficult to defend against IOMMU effectively solves the "DMA is completely broken" problem, as far as I'm aware. Evil Maid attacks are mostly worrisome because even UEFI cannot protect you against some bootloader attacks (what if you disable UEFI or reflash the firmware and then have a bootloader that just looks like a UEFI boot). There are some usages of TPMs that seem quite promising (they revolve around doing a reverse-TOTP-style verification of your laptop to ensure that the TPM has certified the entire boot chain). It's quite a hard problem, made significantly harder by the fact that every fucking hardware vendor seems to want to make our machines even less secure.
- gargravarr 9y ago
  The problem is hard mostly because the entire architecture of the personal computer made absolutely no provision for security. Everything is patches upon patches to add superficial security. Fundamentally, a computer is dumb, it will perform whatever task it is told to do, and all our security measures revolve around stopping a malicious actor from telling the computer to do something 'bad'. Eventually, someone gets around the bouncer or in through an open window and here we are.

cryogenic_soul 9y ago

Many people will now start to dig in. War is started and I hope somebody will find a way to totally remove/replace(with a stub) Intel ME before some critical vulnerability will be discovered in the Intel ME's network stack. In white hats we trust :)

gargravarr 9y ago
Here's hoping. Intel did a great job hiding the thing and making it all but impossible to remove (at present if you nuke the firmware, the CPU will totally fail to initialise. Thanks Intel!). That said, we're talking about an embedded device with very low-level code, and any 'disabling' code is probably going to be distributed in binary form. Stands to reason somewhere along the lines, someone is going to turn that around for their own benefit. In tin-foil hats, we trust, more like!
- arca_vorago 9y ago
  I just get tired of being ridiculed and then 10 years later vindicated. In Faraday cages we trust.
  - gargravarr 9y ago
    2013 was the greatest 'WE TOLD YOU SO' in history for the tin-foil-hat brigade...
    - raverbashing 9y ago
      Why 2013 specifically?
      - cyphar 9y ago
        Presumably because of https://en.wikipedia.org/wiki/Edward_Snowden#Publication https://en.wikipedia.org/wiki/Edward_Snowden#Publication

tinus_hn 9y ago

The vulnerability exists, wether someone reveals it to the public or not. These people found it with Intel keeping the working of the system under wraps as much as possible. You can imagine the kind of access available to people who did get to see the source code. At least now that everyone can see the problem people can make informed decisions.

goldenkey 9y ago
I would think those people are under constant threat of being kidnapped for their information
- sametmax 9y ago
  Given the complexity of the thing, they need a LOT of high profile people to create such a stuff. It's very unlikely none of them have been either: - bribed - threaten - felt guilty about it and decided to make amend My money is that exploits have been on the blacks market for a while now. We just have an official public demo now. Rule of thumb: when something that catastrophic is made public, the worst already happened and you are late to the party.

blhack 9y ago

Is it still true that USB devices can be used to execute code on a target's system without user interaction? I thought this behavior disappeared ~10 years ago.

IshKebab 9y ago
They shouldn't be able to. Firewire devices can because they used DMA without memory protection. I don't think Thunderbolt has the same flaw. However there are bugs in USB stacks, especially now you can do so many alternate protocols over USB-C. https://www.jefftk.com/p/malicious-usb-sticks https://www.jefftk.com/p/malicious-usb-sticks There's nothing fundamental in the USB spec that lets devices execute code on the host.