So Much For Spectre, Here’s Zenbleed!

Source: Ars Technica So Much For Spectre, Here’s Zenbleed!

Swiping Data From Your Registers At 30Kb Per Core, Per Second

If you are running a Zen 2 processor, spanning the Ryzen 3000 and Ryzen 4000G series of desktop processors, the 4000 and many 5000 series of laptop processors as well as the retro cored Ryzen 7020 mobile CPU and finally the Threadripper 3000 family then you are in a bit of a situation.  If you are running an EPYC 7020 you are also in trouble, but unlike the previously mentioned chips there is already a patch available which you should download immediately.   As for everyone else, October through December is the likely time for a patch to become available, though it still needs to be distributed.

As to the situation users are in, it doesn’t get much worse than Zenbleed.  The bug does not require physical hardware access  nor elevated access to to implement, all it takes is some maliciously crafted JavaScript on a website to infect you.  Once on your machine Zenbleed will send out the information passed to your CPU’s registers at a speed that would allow for real time monitoring of the data being processed on your machine.  That includes passwords as well as other data you happen to be processing.

There is a bit of good news to follow the bad; no one has detected it being used in the wild as of yet.  That may change in the coming months, but for now the exploit is simply theoretical.  The other piece of good news is that inserting an emulation layer will defeat Zenbleed completely, and so it might be a good idea to implement on sensitive servers if at all possible.

If you're using Ryzen desktop processors, all Ryzen 3000-series and Ryzen 4000G-series chips (but not Ryzen 3000G, which uses an older Zen version) are vulnerable to Zenbleed. AMD plans to release a firmware fix by December, though your motherboard or PC manufacturer will be responsible for distributing the update.

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About The Author

Jeremy Hellstrom

Call it,, or PC Perspective, Jeremy has been hanging out and then working with the gang here for years. Apart from the front page you might find him on the BOINC Forums or possibly the Fraggin' Frogs if he has the time.

1 Comment

  1. razor512

    Hopefully browser makers or ublock origin devs will add an option to restrict some of those javascript functions that would be needed to perform the exploit.


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