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I'm sure Amazon would love it too (think about how much money they could save / make) but there are a lot of security concerns that need to be addressed. Runnin

I'm sure Amazon would love it too (think about how much money they could save / make) but there are a lot of security concerns that need to be addressed. Running code in a virtualized kernel is a lot more secure than running in the real kernel with permissions limited. Theoretically an exploit could allow someone to take over the machine, whereas if the machine is virtualized it's much harder to take over the host.

toomuchtodo 11y ago
Doesn't matter if the machine is taken over if its properly contained at the network level. Dedicated server hosting companies have been doing this for years.
- skj 11y ago
  With VMs the customer can share a physical host with others and not have security concerns. This cohosting lets aws pack customers more efficiently and have much better margins for the same quality service. With containers on bare metal, they could not cohost customers.
  - toomuchtodo 11y ago
    Uhh, even with containers you really can't cohost in a multi-tenant system. Containerization doesn't securely segregate arbitrary code in the same way traditional virtualization does, and there are still security issues with that. I'm sure AWS is improving on this, as they need to with Lambda and its underlying containerization architecture. But everyone else? Its going to be a while before you can call it "secure".
    - cpitman 11y ago
      It looks like you are in violent agreement
      - toomuchtodo 11y ago
        We are! And I love that phrase :)
- paulannesley 11y ago
  Unless “the machine is taken over” means firmware-level compromise (e.g. disk controller, NIC controller, …), in which case the next customer allocated to that machine can be compromised despite full disk erase between customers.
  - toomuchtodo 11y ago
    I'll agree with this attack vector, although it'd be trivial to have your PXE boot routine between customers re-apply known good firmware to the NIC and disk controller and verify with checksums (unless there's a 0-day out there for the NIC controller, in which case you're owned regardless).
    - hueving 11y ago
      Assuming the firmware has no say in the flashing process.
    - teraflop 11y ago
      Normally the PXE boot code is, itself, stored in firmware.
      - toomuchtodo 11y ago
        Whatever components start first, wins. If the PXE boot code is in the NIC, you can theoretically verify the rest of the system first. If its in the BIOS, the BIOS needs to trust the NIC as untrusted/determine if its compromised or not. Security is hard :/
        XorNot 11y ago
        ROM based NIC? Why not? If you're going into large scale dedicated servers, this is not exactly impractical. You could probably also just disconnect the flash enable pins on the ICs.
- detaro 11y ago
  Amazon offers billing by the hour for those, meaning they probably move between customers a lot more than traditional dedicated servers. A bare-metal user can do lot of bad things unless you trust your hardware manufacturing 100 %, e.g. by messing with the firmware.
  - toomuchtodo 11y ago
    At the hardware purchasing level Amazon operates with for AWS hardware, I'm sure they're able to (if they required it) spec custom BIOS requirements that perform integrity verification of subsystems before permitting power up to continue. Whether they do or not is a different question (although I'm sure someone could test this theory).
    - wtallis 11y ago
      They could also just spec that firmware be stored on ROM rather than flash.
      - tehmaco 11y ago
        Or that a hardware jumper needs to be set on the motherboard before any firmware updates can be done.
  - luhn 11y ago
    Rackspace offers a cloud cum bare metal service called OnMetal. They flash the firmware before putting a new user on a machine.
- omarforgotpwd 11y ago
  It definitely does matter if the host machine is taken over... an attacker could access other customer instances, shut down the system to try and shut down EC2, etc..
  - andrewstuart2 11y ago
    If I've paid for the bare metal machine then by definition I already have root on the host machine. Securing that is just as much my problem at that point as is securing my EC2 instances.
andrewstuart2 11y ago
The security concern you mention (taking over the host) is moot if I've paid for root access to a physical machine (bare metal). By definition I've already paid for the host; there's nothing else to break out of. SDN could easily be handled by an off-system component. I forget who, but someone who presented at ONS 2015 [1] mentioned the use of FPGAs for this. [1] https://www.youtube.com/playlist?list=PLhigroIsbIuet0qlIGBQiSSbeShURXJs_ https://www.youtube.com/playlist?list=PLhigroIsbIuet0qlIGBQi...

toomuchtodo 11y ago

Doesn't matter if the machine is taken over if its properly contained at the network level. Dedicated server hosting companies have been doing this for years.

skj 11y ago
With VMs the customer can share a physical host with others and not have security concerns. This cohosting lets aws pack customers more efficiently and have much better margins for the same quality service. With containers on bare metal, they could not cohost customers.
- toomuchtodo 11y ago
  Uhh, even with containers you really can't cohost in a multi-tenant system. Containerization doesn't securely segregate arbitrary code in the same way traditional virtualization does, and there are still security issues with that. I'm sure AWS is improving on this, as they need to with Lambda and its underlying containerization architecture. But everyone else? Its going to be a while before you can call it "secure".
  - cpitman 11y ago
    It looks like you are in violent agreement
    - toomuchtodo 11y ago
      We are! And I love that phrase :)
paulannesley 11y ago
Unless “the machine is taken over” means firmware-level compromise (e.g. disk controller, NIC controller, …), in which case the next customer allocated to that machine can be compromised despite full disk erase between customers.
- toomuchtodo 11y ago
  I'll agree with this attack vector, although it'd be trivial to have your PXE boot routine between customers re-apply known good firmware to the NIC and disk controller and verify with checksums (unless there's a 0-day out there for the NIC controller, in which case you're owned regardless).
  - hueving 11y ago
    Assuming the firmware has no say in the flashing process.
  - teraflop 11y ago
    Normally the PXE boot code is, itself, stored in firmware.
    - toomuchtodo 11y ago
      Whatever components start first, wins. If the PXE boot code is in the NIC, you can theoretically verify the rest of the system first. If its in the BIOS, the BIOS needs to trust the NIC as untrusted/determine if its compromised or not. Security is hard :/
      - XorNot 11y ago
        ROM based NIC? Why not? If you're going into large scale dedicated servers, this is not exactly impractical. You could probably also just disconnect the flash enable pins on the ICs.
detaro 11y ago
Amazon offers billing by the hour for those, meaning they probably move between customers a lot more than traditional dedicated servers. A bare-metal user can do lot of bad things unless you trust your hardware manufacturing 100 %, e.g. by messing with the firmware.
- toomuchtodo 11y ago
  At the hardware purchasing level Amazon operates with for AWS hardware, I'm sure they're able to (if they required it) spec custom BIOS requirements that perform integrity verification of subsystems before permitting power up to continue. Whether they do or not is a different question (although I'm sure someone could test this theory).
  - wtallis 11y ago
    They could also just spec that firmware be stored on ROM rather than flash.
    - tehmaco 11y ago
      Or that a hardware jumper needs to be set on the motherboard before any firmware updates can be done.
- luhn 11y ago
  Rackspace offers a cloud cum bare metal service called OnMetal. They flash the firmware before putting a new user on a machine.
omarforgotpwd 11y ago
It definitely does matter if the host machine is taken over... an attacker could access other customer instances, shut down the system to try and shut down EC2, etc..
- andrewstuart2 11y ago
  If I've paid for the bare metal machine then by definition I already have root on the host machine. Securing that is just as much my problem at that point as is securing my EC2 instances.

andrewstuart2 11y ago

The security concern you mention (taking over the host) is moot if I've paid for root access to a physical machine (bare metal). By definition I've already paid for the host; there's nothing else to break out of. SDN could easily be handled by an off-system component. I forget who, but someone who presented at ONS 2015 [1] mentioned the use of FPGAs for this. [1] https://www.youtube.com/playlist?list=PLhigroIsbIuet0qlIGBQiSSbeShURXJs_ https://www.youtube.com/playlist?list=PLhigroIsbIuet0qlIGBQi...