Side channel that leaked data from Intel CPUs patched by silent Windows update

https://arstechnica.com/information-technology/2019/08/silent-windows-update-patched-side-channel-that-leaked-data-from-intel-cpus/

by headalgorithm • 7 years ago

139 58 7 years ago

arstechnica.com

edwintorok3• 7 years ago

As mentioned in the article more technical details can be found in the linked article: https://www.bitdefender.com/business/swapgs-attack.html

Worth pointing out that Xen is not vulnerable to the swapgs attack due to a lucky design decision from a decade ago: https://lists.xenproject.org/archives/html/xen-devel/2019-08...

tinco7• 7 years ago

I know these problems are serious, but I feel there is a fun and reassuring aspect to them. Back in the 90s and early 2000s we thought anything can be hacked by any clever person. Then the 2010s happened and almost all software, even Windows, became near unassailable fortresses, especially systems like iOS with their tight control of the OS. Sure, a 0day drops every now and then, but we all know that it's basically impossible to attack a modern well configured system.

These hardware bugs turn that idea on its head, suddenly the whole ghost in the shell hacker style dream is again a possibility. A motivated person or group of persons might go and hack any system out there. And that's really a bit reassuring, it's a little bit scary to think about how our lives might be ruled by these systems that are unassailable. I'd like to at least stand a chance when technology turns on us.

d2mw2• 7 years ago

we all know that it's basically impossible to attack a modern well configured system

Where in the world did this fantastic idea come from?

https://events.linuxfoundation.org/wp-content/uploads/2017/1...

https://en.wikipedia.org/wiki/Pwn2Own#Summary_of_successful_...

https://threatpost.com/baseband-zero-day-exposes-millions-of...

tinco7• 7 years ago

How many of those kernel bugs translate to meaningful RCE's in generally available stable software? Maybe I'm out of the loop, but as that presentation says nowadays a big 0day will have a logo and national headlines, that also underlines how rare they are.

To me the history of Pwn2Own exactly shows the trend I'm talking about. Going from very successful editions to increasingly less successful editions as the years go by to the point where the competition barely even exists anymore.

And then that baseband firmware exploit, that's the dream. You could hack any device with that almost regardless of what software runs on top. I put that in the same class as the Intel chip vulnerabilities.

userbinator• 7 years ago

Keep in mind that all these speculative execution exploits rely on being able to already execute code on the target, they can only read data somewhat slowly, and where the data you want to read is in a 64-bit address space is not easy to find.

The media loves to blow things out of proportion, but all the specexec attacks are really not as big a deal as e.g. remote code execution. In some ways, they are the real-world equivalent of "you can sometimes hear things your neighbours say, with a sensitive microphone and lots of patience."

tedunangst• 7 years ago

How lucky then that we all live in the cloud now and running code on other people's computers is the only place anybody runs code anymore.

cjbprime3• 7 years ago

This is somewhere between misleading and wrong -- Spectre-ish attacks can be conducted by JavaScript when you visit a random web page. It's mostly appropriately-proportioned.

edwintorok3• 7 years ago

JavaScript can run code on your computer, and used to be possible to get accurate timings out of it.

badrabbit• 7 years ago

It's more like in the 90s and 2000s software-exploit based attacks were fairly easy. These days you have to adopt and use logical,social and configuration vulnerabilities that have always been common as well.

tinco7• 7 years ago

Imagine the damage those ransomware people could have done back then.. Whole countries were open for disruption.

JohnJamesRambo• 7 years ago

I think the amount of people damaged by hacks exceeds the numbers saved in your scenario by several orders of magnitude. In fact your post is one of the first I’ve ever read that sees software and hardware vulnerabilities as a good thing.

tinco7• 7 years ago

I'm not saying they are a good thing per se, just a reassuring thing. It means we still need to be in control of our systems, and can't blindly let our systems control us, because indeed they are fallible. It's of course rather philosophical.

There's also a big difference between these sort of vulnerabilities, and the sort of problems that enable for example ransomware, which is a serious issue that has a more difficult solution than simply designing more robust hardware.

Anyway, if you're intrigued maybe check out Ghost in the Shell sometime (not the one with Scarlett Johansson, although it is enjoyable, it's not really the same thing), if it needs to be Hollywood, then maybe the Hackers movie would also work a bit (with Angelina Jolie).

Spooky23• 7 years ago

There is definitely an argument to be made. Discovery of these bugs improves software. If not for Blaster/Welchia years ago, Microsoft would not have empathized security or quality in their products for years.

umvi• 7 years ago

Then the 2010s happened and almost all software, even Windows, became near unassailable fortresses

Maybe from remote attacks, but nothing can defend against a good ol' keylogger, not even 2FA.

tinco7• 7 years ago

A proper 2FA implementation would surely defend against keyloggers? Unless your concern is leaking information?

ailideex2• 7 years ago

Back in the 90s and early 2000s we thought anything can be hacked by any clever person.

We did?

dylan604• 7 years ago

I was thinking that might have been true back in the 80s. Hell, I still feel that way about anything analog. It's just nothing is really analog any more. Once things went digital and encryption was implemented, things just became more of a social engineering type of hack to get people to give you the information to walk in the front door. It's not that you hacked the Gibson or anything. Also, modern systems just don't have the cool 3D interfaces that all of the systems from the 80s/90s had ;-)

tinco7• 7 years ago

Yes.. Windows XP had an unending list of vulnerabilities, software patch policies were often horrible, hardware with outdated software was everywhere. Back then if you would call yourself a hacker or a hack group it would mean you had multiple 0day exploits under your sleeve for operating systems, browsers and web apps.

Even if you were just a lowly scriptkiddie, because of the bad update policies you could just go to an exploit website, like metasploit is now, and try out the list of old exploits on any target you were interested in. A friend of mine had 40.000 routers in some Scandinavian country because their ISP shipped them to customers with a 4 year old BSD release that had known vulnerabilities in it.

swebs• 7 years ago

Pretty much. Security wasn't really seen as something developers worried about back then. Maybe it was because there were less bad actors due to it being much harder to make a buck through hacking. I remember setting up a server with an extremely weak SSH password around 2003 and it went for months without receiving any sort of traffic at all, much less login attempts. Nowadays if you set up a server with port 22 open you'll get dozens of hits per day from various bots scanning the entire IPV4 range and trying dictionary attacks to get in. Going through Fail2ban logs can be pretty entertaining.

jayd16• 7 years ago

unassailable fortresses, especially systems like iOS

It hasn't been particularly hard to jailbreak iOS or root Android devices if you have physical access. We've seen several hilarious examples of exploits over the years regarding lock screen bugs or magic SMS parsing bugs.

OrgNet• 7 years ago

we all know that it's basically impossible to attack a modern well configured system.

you must be living in a different world...

iamnotacrook• 7 years ago

"2010...Windows... became near unassailable fortresses"

Did anyone read this and not laugh out loud?

"These hardware bugs turn that idea on its head, suddenly the whole ghost in the shell hacker style dream is again a possibility"

No, it was always a possibility.

imglorp• 7 years ago

Something interesting did happen around that time. Looking at all CVEs as an aggregate, it appears 2008ish is about when there was an inflection, perhaps a shift from OS to injection/validation/appsec?

https://nvd.nist.gov/general/visualizations/vulnerability-vi...

novaleaf• 7 years ago

I left msft in 2007 and at that time they were in full "security is important" mode. Due to backcompat it's of course hard (impossible?) to remove local exploits, but RCE is a lot harder. For example I don't know the last time I heard about a windows RCE. Edge/IE sure, but not windows. Windows Defender is a very good security product, and Windows Update "just works".

makomk• 7 years ago

Even though it's supposedly not feasable to exploit on Linux, there are fixes in the upstream kernel now and the changelog entries have some technical details. If I'm understanding this correctly, AMD systems don't speculatively execute GS-based accesses after speculatively excuting SWAPGS like Intel ones do, but that isn't enough to fully fix the problem on Linux because there's a conditional branch over the SWAPGS instruction which can be speculatively executed. Since that execution path doesn't have a SWAPGS all processors will quite happily continue speculatively executing code that fetches data via GS.

menzoic2• 7 years ago

What does speculative mean in this context?

viraptor• 7 years ago

CPU speculating that it knows what the state will be after SWAPGS and continuing to load instructions into pipeline and partially executing them. In case of either a different branch bring taken, or SWAPGS causing a fault the pipeline will be rolled back, but side effects of the partial execution (like loads into cache) will not be.

proactivesvcs• 7 years ago

It seems rather unfair to make the statement that "Microsoft silently patched the vulnerability during last month's update Tuesday" where the phrase "patched the vulnerability" links to Microsoft's CVE article on the problem.

wademealing2• 7 years ago

I agree its unfair.

Microsoft also played ball with Linux vendors alerting them to this vector. This allowed them to get the swapGS fixes tested and sane.

This interaction with the opensource community has significantly increased my respect for Microsoft.

jnordwick3• 7 years ago

Whitepaper is behind a wall, so I can't read it, but I assume it is another in the large and growing class of explits that cannot practically be exploited like Spectre or the load-store buffer that didn't stand a snowballs chance in Hell or creating a workable exploit that didn't' require immense cooperation from the target (literally accessing the same address in a loop and and nothing else).

Still no spectre exploit (or even attempt) found in the wild. There should have been something by now.

If anybody has access to the POC code I would love to see it. Until (and probably after I see how laughable it is), I'll assume this is just a press release by some security company.

wademealing2• 7 years ago

I believe that this (SWAPGS) vector is impractical but previous spectre proof of concepts exists if you look hard enough.

jnordwick3• 7 years ago

I have never seen one that would work in the wild. I don't think it is possible. We've had plenty of time to see something somewhere, but nothing. I gone through the papers, read other code, I've seen nothing that didn't require help from the target.

I don't accept the general hand waving "they keep getting better" because they haven't.

Most of these the exfiltration rate is so slow that simply xor'ing the secret with a random seed that changes locations or moving the memory around itself would prevent any attack.

mschuster91• 7 years ago

literally accessing the same address in a loop and and nothing else

All you need for this is Javascript with Web Workers to run effectively multithreaded.

jotm2• 7 years ago

What's the performance hit on this one?

GrumpyNl• 7 years ago

What i understand is , you are already hacked when they perform this hack. They already have access to your system.

jaclaz• 7 years ago

Noone is concerned by the concept of "silent" Windows update?

Multicomp• 7 years ago

So I have not yet installed the July 'security only' update because it contains W10 style telemetry (I'm on Windows 7 group B for the fellow AskWoody-ians) which I abhor even more than being vulnerable to a hack.

Any way to get the good without the reprehensible?

Side channel that leaked data from Intel CPUs patched by silent Windows update

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