El Reg: Researchers steal data from CPU cache shared by two VMs

Researchers steal data from CPU cache shared by two VMs

A group of researchers say they can extract information from an Amazon Web Services virtual machine by probing the cache of a CPU it shares with other cloudy VMs.

A paper titled Hello from the Other Side: SSH over Robust Cache Covert Channels in the Cloud (PDF) explains the challenges of extracting data from CPU cache, a very contested resource in which the OS, the hypervisor and applications all conduct frequent operations. All that activity makes a lot of noise, defying attempts to create a persistent communications channel.

Until now, as the researchers claim they've built “a high-throughput covert channel [that] can sustain transmission rates of more than 45 KBps on Amazon EC2”. They've even encrypted it: the technique establishes a TCP network within the cache and transmits data using SSH.
The results sound scarily impressive: a Black Hat Asia session detailing their work promised to peer into a host's cache and stream video from VM to VM.

The paper explains that this stuff is not entirely new, but has hitherto also not been entirely successful because it's been assumed that “error-correcting code can be directly applied, and the assumption that noise effectively eliminates covert channels.”

The authors knock both of those arguments over, the first by figuring out a way to handle errors and the second with a method of scheduling communication between two VMs.
The paper details those efforts extensively, names them a “Cache-based Jamming Agreement” and offer you working code on GitHub so you can build your own all-in-cache covert channel, either on-premises or in the cloud.

Like I've Been Sayin' - you don't need a full OS in the cloud

From Slashdot 24-Mar-2013:

 "Virtual servers in the future may stop using OSes entirely. As recently demonstrated OS-less platforms may change our understanding of how long does it take to bring a server up. A demo server gets created, booted up, configured, runs an application and shuts down in under 1 second. ... The demo uses a new Erlang runtime system capable of running directly on Xen hypervisor."

In a nutshell, what is Erlang?
Erlang is a general-purpose programming language and runtime environment. Erlang has built-in support for concurrency, distribution and fault tolerance. Erlang is used in several large telecommunication systems from Ericsson. Erlang is available as open source from http://www.erlang.org.

Here is the demo screen for "Zerg", an example of an application the starts an instance of a server in the cloud, using Erlang on Xen, which sends a page and deletes itself, in .6 seconds.  Compare that to 5 minutes for the same thing on Amazon EC2

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Yet another danger of cloud computing...

From an article in Ars Technica, "For example, if the government accidentally seized iCloud servers containing the only copy of priceless family photos, you'd need to be prepared to explain why there are pirated MP3s in your iTunes folder."

 The user who was an example a paid customer of Megaupload wants his business files back.  The DOJ looked at the contents, and found "numerous videos produced by Mr. Goodwin have as their soundtracks recordings of popular copyrighted music." and "music files with MD5 values that matched the hash values of pirated versions of popular music"

IANL, but it looks to me like a storage facility that was seized by the government, and its users want their spaces back.  If the facility was seized for a pattern of housing stolen property, and that's what the customers have in their spaces...  Well?  How about customers that have non-stolen property commingled with thing that are provably a problem?

Well, I guess the standard recommendations for cloud computing still stand, maybe now more than ever.

Our hearts and prayers go out to the people in the mid atlantic states in the wake of the hurricane  :-(

How good is The Cloud?

Well, it depends.  Remember, you're using someone else's servers.  If they slip, and you lose stuff, what are your options?

Here's the story of Kyle Goodwin, as told in his Motion For Return of Property to the US District Court in Virginia.  He was a Premier paying customer to MegaUpload (remember KimDotCom?), and stored his small business's backups of his video files there.

His hard drive crashed, and within hours the US and New Zealand courts had shut down MegaUpload's servers, shutting off access to Mr Goodwin's data.  It's stored in MegaUpload's colo site, bit turned off and unavailable.

So don't worry, the cloud is fine, your data on the other hand,  Reply hazy, try again.