OpenBSD Chief De Raadt Says No Easy Fix For New Intel CPU Bug 'TLBleed' (itwire.com)

Recompiling is unlikely to be a catch-all solution for a recently unveiled Intel CPU vulnerability known as TLBleed, the details of which were leaked on Friday, the head of the OpenBSD project Theo de Raadt says. iTWire reports: The details of TLBleed, which gets its name from the fact that the flaw targets the translation lookaside buffer, a CPU cache, were leaked to the British tech site, The Register; the side-channel vulnerability can be theoretically exploited to extract encryption keys and private information from programs. Former NSA hacker Jake Williams said on Twitter that a fix would probably need changes to the core operating system and were likely to involve "a ton of work to mitigate (mostly app recompile)." But de Raadt was not so sanguine. "There are people saying you can change the kernel's process scheduler," he told iTWire on Monday. "(It's) not so easy."

He said that Williams was lacking all the details and not thinking it through. "They actually have sufficient detail to think it through: the article says the TLB is shared between hyperthreading CPUs, and it is unsafe to share between two different contexts. Basically you can measure evictions against your own mappings, which indicates the other process is touching memory (you can determine the aliasing factors)." De Raadt said he was still not prepared to say more, saying: "Please wait for the paper [which is due in August]."

Comments

Illusion of speparation in VM

[sinij]

If not this one, maybe the next bug of this kind will finally put illusion of VM separation to rest. If you are running something in the cloud, there is no way to secure it. Start bringing important stuff back in-house, and better use dedicated hardware. Yes, these old-fashioned blade servers were in the access-controlled server room for a reason.

Special settings

[duke_cheetah2003]

Like Meltdown and Spectre, this 'exploit' requires a lot of things to be 'just right' for an exploit or data leak to occur.

I'm not saying they're worthless exploits, but again, when I read some of the particulars about the research.. well this popped out:

The team used AI – specifically, a support vector machine classifier – to identify when a program is executing a sensitive operation, such as a cryptographic function, through the TLB latencies, and read out that app's private data as a stream of bits, allowing them to reconstruct things like crypto keys. There are hurdles to overcome, such as address-space layout randomization – however, the team believes these can be defeated in real-world attacks.

So I really don't know a lot about AI implementations, but I'm going to take a liberty and say, that's probably computationally expensive to be doing. That they needed an AI to even get anywhere examples how sensitive this exploit truly is. Expecting to deploy an AI in the wild (malware) and have it grabbing stuff from whatever... it's a pretty big stretch from these laboratory conditions to real-world.

I'm not going to say there's nothing here, but I am going to say: Where's the beef? Cuz it's awfully small with this exploit, there's much easier ways to steal information.

Lastly, it seems isolated to HyperThreading Intel CPUs, from what I read. Yes, it's a big attack surface, but still.. an exploit working in your special setting doesn't really move me much, especially how special these particular set of conditions were.

Re:Special settings

[93 Escort Wagon]

Theo: Worried
Random Slashdotter: Not so worried

No offense, but I’ll go with the OpenBSD and LibreSSL guy on security matters.

Re:I am an old nobody

[grep -v '.*' *]

I know, I know nothing, I wrote z80 assembly as an intro.

I learned on an MITS Altair-8800 computer that my roommate had in college. We played one dimensional, straight-line Pong, and had to flip the front-panel switches to reload the program after shutting it off. (5.1 Audio? Mouse? CRT? Printer? Floppy? Keyboard? Paper-tape? You must be joking.)

After graduation, I ended up at his computer shop running CDOS, a CP/M improvement from Cromemco with hardware. They eventually upgraded from 8080 to a Z-80. Really neat, with those 2nd set of registers. We wrote COBOL and Fortran accounting software using embeeded software overlays and 8" floppies and 5-10M hard drives. (150K? 5 Meg? Is that right?? We only had 64K of RAM though, MAX) for companies.

Hey, did you ever see that Zilog Z-80 paperback book (6"x8"? Weird size.) describing how all of the operations worked in pseudo-code? It was wonderful.

I still have a Z-80 fold-out instruction card. Also an IBM 360 one, much longer. Not much useful now, but extremely useful at the time.

Also, decades ago now, IBM produced (as an experiment, not a retail product) a mainframe computer-on-a-chip, but supposedly the firmware was changeable to directly run binary code from IBM 360, PDP, Amdahl, and maybe 3 other CPUs. A decade or more later you've got (we had internal Compaq In-Site cards) things which directly control the computer remotely, even when "it's off". I understand the new corporate ones have it all built on the motherboard. Still need power to the PS though, but you could insert floppy images and flash firmware while sitting at your desk. Neat-O!

I used to understand how things worked, down to the bare metal. (Could program PICs and INT handlers and all that. You too, I'm sure. Remember 16550 UART serial chips with 14-byte internal cache? ) I fiddled with AI a bit in college in the late 70s. It was bloomin' math magic then, I could run the simple operations by hand or look at the intermediate data structures. But it was all just random junk -- except it would actually come out with working answers. I can't imagine and don't understand what they're doing now -- and really, I don't actually think they do either.