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BlogLinodeVulnerabilidades de la CPU MDS (ZombieLoad) de Intel & Linode

Vulnerabilidades de la CPU MDS (ZombieLoad) de Intel y Linode

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Esta semana Intel reveló públicamente un grupo de vulnerabilidades en los procesadores conocido como Muestreo de datos microarquitectónicos (MDS)también conocido como "ZombieLoad". MDS afecta a los sistemas que alojan máquinas virtuales de diferentes dominios de seguridad y/o en los que el propietario del sistema no confía plenamente, lo que incluye la infraestructura de Linodey los propios Linodes. Esta guía tiene información detallada adicional sobre estas vulnerabilidades así como su mitigación.

Hemos comenzado los esfuerzos de mitigación y anticipamos la mitigación completa de nuestra flota en las próximas semanas. Estos esfuerzos de mitigación pueden requerir la interrupción de sus sistemas en funcionamiento, pero comunicaremos claramente cualquier mantenimiento programado o la coordinación requerida por nuestros clientes a través del ticket de soporte.

Para solucionar estas vulnerabilidades, hemos lanzado un nuevo kernel (5.1.2) con mitigaciones, así que asegúrese de seleccionar este kernel en su perfil de configuración de Linodey luego reinicie. Si está utilizando un núcleo suministrado por la distribución, tendrá que actualizar su kernel en consecuencia. Como siempre, debes asegurarte de que tu Linode está actualizado y asegurado.

Les mantendremos informados aquí en las próximas semanas a medida que avancemos en nuestros esfuerzos de mitigación.


Comentarios (13)

  1. Author Photo

    Is the “Latest 64-bit” Kernel going to be sufficient or do all servers need to be using the 5.x kernel?

    • Author Photo

      Hey, Jim. At the moment, the “Latest 64-bit” kernel is not patched for MDS — we’ve delayed changes due to a kernel bug involving inaccurate ‘uptime’ reports. We instead recommend booting into 5.1.2-x86_64-linode124 for 64-bit systems, or 5.1.2-x86-linode144 for 32-bit systems. Once the kernel bug has been completely resolved, you could then switch back to the “Latest”.

  2. Author Photo

    Linode offer two 5.1.2 kernels. One is 5.1.2-x86-linode144 and caused kernel panic on Debian 9. 5.1.2-x86_64-linode124 works. Thanks to support for guiding me to this point. It should be added to the post here.

    • Author Photo

      Hi there, John. The 5.1.2-x86-linode144 kernel is designed for 32-bit systems. It will not work properly on 64-bit systems. For 64-bit systems you will want to use the 5.1.2-x86_64-linode124 kernel. For all 64-bit systems you will want to look for the kernels that include “_64” in the title.

  3. Author Photo

    Any particular reason for the “latest-kernel” to stuck at 4.18.6 ?

  4. Author Photo
    Benjamin A Blouin

    Update?

  5. Author Photo
    طراحی سایت

    Great and useful post, Thanks for sharing
    Bookmarking the blog for future reference.

  6. Author Photo

    What is the expected performance impact of the mitigation?

    • Author Photo

      Viktor: We don’t anticipate performance impacts coming from ZombieLoad mitigation. However, disabling HyperThreading as part of our mitigation strategy for speculative operation vulnerabilities poses a clear challenge regarding performance, so accordingly we’ve been working to minimize its impact on our platform. (You can find more discussion on HyperThreading here.)

      If you’re seeing degraded performance on any of your Linodes, please reach out to us so we can help investigate and find a solution.

  7. Author Photo

    Can we use the new kernel for Debian 7 machines?

    • Author Photo

      Hi Mike – Yes. No issues with our latest kernel and Debian 7. I’d recommend reading through our Reboot Survival guide, though, if it’s been awhile since you’ve needed to reboot some of your machines:

      > https://www.linode.com/docs/guides/reboot-survival-guide/

      If you’ve regularly kept your server up to date, issued reboots periodically and have always used the latest kernel, you’re more likely to be okay if you continue to use it. Having a restore plan in place in the event anything goes wrong is always recommended, though, since there are a lot of variables at play.

  8. Author Photo

    Other posts mentioned a live-migration capability now. That doesn’t work for host updates?
    Are you moving towards the only needed reboots to be for upgrade/downgrades and updating our kernel?

    • Author Photo

      Hi Avi – Technically speaking, for small scale host updates, live migrations would work. Though since CPU vulnerability mitigation is a much larger effort, it’s logistically more efficient to cold migrate servers to patched hosts, or apply the needed patches during the maintenance window. As for your second question:

      > Are you moving towards the only needed reboots to be for upgrade/downgrades and updating our kernel?

      Yes, though this is a long term effort, and I don’t have anything immediate to share regarding an ETA.

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