[HN Gopher] Hot Pixel' Attack Steals Data from Apple, Intel, Nvi...
       ___________________________________________________________________
        
       Hot Pixel' Attack Steals Data from Apple, Intel, Nvidia, and AMD
       Chips
        
       Author : uguuo_o
       Score  : 73 points
       Date   : 2023-05-27 13:41 UTC (9 hours ago)
        
 (HTM) web link (www.tomshardware.com)
 (TXT) w3m dump (www.tomshardware.com)
        
       | vrtnis wrote:
       | Table 19 from the paper seems to show pixel extraction accuracy
       | is highest for AMD Radeon (94%) but lower for M1/M2 (~60%). Can't
       | seem to find an explanation for this variation though. Thoughts?
        
       | ngneer wrote:
       | This highlights subtly different thinking processes in the
       | security industry. Real world adversaries think "this is an
       | interesting asset, how can we get to it, with our available
       | primitives?" whereas academic researchers think "this is an
       | interesting primitive, what kind of assets would make the paper
       | work?".
        
       | slashdev wrote:
       | > By forcing one of the three variables of DVFS (heat, power, or
       | frequency) to become a constant, the researchers can then monitor
       | the other two variables to distinguish which instructions are
       | being executed, even with enough precision to ascertain the
       | different operands of the same instruction.
       | 
       | Sounds like one of those attacks that works in theory but is too
       | impractical to use in real life. This is harder than cache side
       | channel attacks, and we still haven't seen much use of those in
       | the wild, years later.
       | 
       | > Ultimately, this furthers other attacks, like website
       | fingerprinting.
       | 
       | Umm no. Did ChatGPT write that? Fingerprinting isn't an attack
       | and that's not how it works. Also this requires access to system
       | temperatures and other metrics that are absolutely not available
       | from JavaScript.
        
         | cumshitpiss wrote:
         | [dead]
        
         | formerly_proven wrote:
         | > Also this requires access to system temperatures and other
         | metrics that are absolutely not available from JavaScript.
         | 
         | The Chrome developers at Google are preparing a WebHWiNFO
         | proposal as we speak.
        
           | jwilk wrote:
           | You reminded me of this: https://twitter.com/twowordhorror
        
         | Xeoncross wrote:
         | > that are absolutely not available from JavaScript
         | 
         | No problem, just use a zero-day to get full system access and
         | then you can read the temps and send them back to JavaScript.
        
         | kwantam wrote:
         | The paper, which is linked from the article, demonstrates a
         | browser "fingerprinting" attack, which is to say, stealing
         | pixels from one iframe using another iframe (which is quite
         | clearly a violation of the safety properties the browser is
         | supposed to provide).
         | 
         | It's unfortunate that this article is poor, but the paper
         | itself is clear and readable.
        
           | slashdev wrote:
           | Why do they call that browser fingerprinting? That's a
           | clearly a violation of browser isolation policies, but I
           | don't see the connection to fingerprinting. Also there are
           | much easier ways to do actual fingerprinting. That involves
           | finding a large number of statistically unique things and
           | combining them to identify repeat visits from a particular
           | device without cookies or local storage.
        
             | ngneer wrote:
             | I think it is less about a server fingerprinting a client
             | and more about one website using broken browser isolation
             | to fingerprint other websites being visited. In the
             | example, they leak whether a pixel is black or white by
             | scaling it to fit the full canvas and then triggering
             | 200-400 renders.
        
             | SideQuark wrote:
             | Different browsers will leak different data from this (and
             | subsequent) methods. And so what if there are some easier
             | things one can gather; fingerprinting relies on gathering
             | many things. You claim it needs a "large number of
             | statistically unique" items, which is wrong. One
             | statistically unique item is enough, but that's hard.
             | 
             | What is actually used is enough (not large, not small, not
             | one usually... just enough) items with some spread in
             | statistics such that one gathers enough such things so they
             | can conclude to some level of certainty the device is
             | uniquely determined.
             | 
             | Thus any new piece of data that provides any amount of
             | device discrimination is useful. This new method fits the
             | bill. And it will open the door to much more advanced
             | attacks, as all new attacks do.
        
       | alain94040 wrote:
       | I found the paper didn't live up to its claims. It said: _the
       | ever-changing behavior of these SoCs is also visible via internal
       | measurement sensors, allowing us to distinguish between executed
       | instructions, and even different operands of the same
       | instruction_
       | 
       | But when you read further and see what they tried:
       | 
       |  _We then selected one Arm instruction from each data-processing
       | bucket,testingstores(str),AESinstructions(aese, aesmc), rotate
       | right (ror), bitwise and (and), and both integer and floating-
       | point addition (add, fadd) and multiplication (mul, fmul). We run
       | each instruction in a loop on all available P-cores on each test
       | device_
       | 
       | What they did is define a handful of known workloads, with very
       | different power profiles. And then they find that they can tell
       | them apart by looking at the power of the chip. Well, duh.
        
       | jmclnx wrote:
       | >The attack requires data from the PC's internal power, temp, and
       | frequency sensors, but this information can be accessed from user
       | accounts that don't have administrator access
       | 
       | Looks like only a local user can do this, but the article is not
       | to clear on that.
       | 
       | Anyway this seems very hard to do. Also I wonder if using
       | OpenBSD's port obsdfreqd can prevent this. Based upon usage, it
       | will adjust the frequency and CPU Temp on the fly.
       | 
       | https://tildegit.org/solene/obsdfreqd
       | 
       | edit: grammer
        
       ___________________________________________________________________
       (page generated 2023-05-27 23:01 UTC)