Google Online Security Blog: Today's CPU vulnerability: what you need to know

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The latest news and insights from Google on security and safety on the Internet

Today's CPU vulnerability: what you need to know

2018年1月3日

Posted by Matt Linton, Senior Security Engineer and Pat Parseghian, Technical Program Manager[Google Cloud, G Suite, and Chrome customers can visit the Google Cloud blog for details about those products][For more technical details about this issue, please read Project Zero's blog post]Google’s Project Zerospeculative executionMitigation status for Google productshere

All Google products not explicitly listed below require no user or customer action.

Android

Devices with the latest security update are protected. Furthermore, we are unaware of any successful reproduction of this vulnerability that would allow unauthorized information disclosure on ARM-based Android devices.
Supported Nexus and Pixel devices with the latest security update are protected.
Further information is available here.

Google Apps / G Suite (Gmail, Calendar, Drive, Sites, etc.):

No additional user or customer action needed.

Google Chrome

Some user or customer action needed. More information here.

Google Chrome OS (e.g., Chromebooks):

Some additional user or customer action needed. More information here.

Google Cloud Platform

Google App Engine: No additional customer action needed.
Google Compute Engine: Some additional customer action needed. More information here.
Google Kubernetes Engine: Some additional customer action needed. More information here.
Google Cloud Dataflow: Some additional customer action needed. More information here.
Google Cloud Dataproc: Some additional customer action needed. More information here.
All other Google Cloud products and services: No additional action needed.

Google Home / Chromecast:

No additional user action needed.

Google Wifi/OnHub:

No additional user action needed.

Multiple methods of attack
To take advantage of this vulnerability, an attacker first must be able to run malicious code on the targeted system.
The Project Zero researchers discovered three methods (variants) of attack, which are effective under different conditions. All three attack variants can allow a process with normal user privileges to perform unauthorized reads of memory data, which may contain sensitive information such as passwords, cryptographic key material, etc.
In order to improve performance, many CPUs may choose to speculatively execute instructions based on assumptions that are considered likely to be true. During speculative execution, the processor is verifying these assumptions; if they are valid, then the execution continues. If they are invalid, then the execution is unwound, and the correct execution path can be started based on the actual conditions. It is possible for this speculative execution to have side effects which are not restored when the CPU state is unwound, and can lead to information disclosure.
There is no single fix for all three attack variants; each requires protection independently. Many vendors have patches available for one or more of these attacks.
We will continue our work to mitigate these vulnerabilities and will update both our product support page and this blog post as we release further fixes. More broadly, we appreciate the support and involvement of all the partners and Google engineers who worked tirelessly over the last few months to make our users and customers safe.

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