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Hackers can steal 2FA codes and private messages from Android phones

• mouse_ 1y ago
  Would you buy a hammer that can't ever hurt your thumb? What implications would that have? Would that be a good hammer? Bad opinion time that I hope will maybe at least be thought provoking: I would hope a malicious app I willingly installed will be able to behave maliciously. Our security bureaucracy is going to grow exponentially and people are still going to be stealing people's shit, because people need to be able to access their shit and people are dumb.
  • leakycap 1y ago
    > requires no [Android] permissions I think this is the part people are upset about
  • akerl_ 1y ago
    > Would you buy a hammer that can't ever hurt your thumb? Yes.
    • elmerfud 1y ago
      I believe those hammers are made by Nerf. Now go build a house with one.
      • rootusrootus 1y ago
        There was a time when we would have said something similar for table saws that cannot cut off your finger. Might be a little harder to pull off the trick with a hammer, but it just seems like another engineering problem. And it would make for a very expensive hammer.
        • elmerfud 1y ago
          It probably wouldn't be classified as a hammer anymore. You're comparing apples and oranges. Now when you show me the manual hand saw that can avoid cutting off your fingers you'll have an accurate comparison. Because we're not comparing air nailers or electric nail guns or screw guns. It was about a hammer. Your comparison is so ridiculous because the table saw did not obsolete any other kind of saw. It was only a new type of saw that allowed for some types of sawing to be done much easier.
          • akerl_ 1y ago
            I'll bite, I guess. The saw stop wasn't a replacement for manual saws. Table saws existed (and still exist!) and have a nasty habit of removing people's fingers. The saw stop was designed as a better table saw. The point being that it's wild to start with the idea that hammers must be a danger to thumbs, and then double down by trying to claim that any hammer that wasn't a danger to thumbs wouldn't be called a hammer. Getting a table saw with a saw stop on it doesn't make it not a table saw.
            • elmerfud 1y ago
              But table saws are a replacement for manual saws. Table saws weren't invented first. Table saws fulfilled a niche use case for sawing. So by that saw stop is a replacement for a manual saw. If you've ever used a hammer, a tool that has been around for tens of thousands of years, you will know by it's very nature of its operation it is a danger to thumbs. Trying to think that you can do "on an iPhone" and start with the assumption that a hammer fulfilling the functions and utility that it has and has had for 10,000 years cannot be a danger to thumbs is an erroneous thought and it shows the height of hubris. Can you have tools that fulfill some of the functions of the hammer that are not dangerous to thumbs? Absolutely and we have those already. Any of the automatic nailers have built-in safety features to prevent accidents. Sometimes people disable those safety features because they do cause problems in legitimate use cases but they are built with those safety features. This would be analogous to saw stop which works in table saws which is a very limited saw. Just like a table saw cannot fulfill all of the functions of a hand saw. A device that pounds nails or other things that has features to prevent it from accidentally hitting thumbs would not be able to fulfill all of the functions of the hammer. From what we've seen with saws, this is your example not mine, all of the electric saws that have ever been built have never been able to eliminate the usefulness or utility of the simple handsaw which is dangerous to use. So where is the hubris to say that because you can invent a safer nailing device, which they have, it will somehow supplant and replace the hammer? The evidence says that's not the case.
      • TZubiri 1y ago
        Would you buy an electric saw that cannot damage your fingers? https://www.youtube.com/watch?v=oQu3ccfl7Ow https://www.youtube.com/watch?v=oQu3ccfl7Ow Or you would yell at a cloud?
        • elmerfud 1y ago
          Everybody knows about saw stop. But in what way does a table saw compare with a hammer? If you were comparing it to an air nailer, or an electric nail gun, or an electric screw gun, which all can have safety features that require certain things to be met before it will fire then you have a comparison. If you want to compare the hammer to something that saws you would compare it to a handsaw. Show me the hand saw that cannot damage your fingers. You must think you're very smart but I don't think you've done any manual labor in your life. Because the table saw never obsoleted any other type of existing saw. It was simply a new tool that enhanced the ability to do certain types of sawing. The more you limit a function of something the easier it is to put guardrails around it. That was the original poster's point. You can limit Android to the point that it is nearly useless or useless only for the most basic of tasks but then you remove the power of it but you do not remove the need for all of the other tasks. Table saws with saw stop still necessitate hand saws in some circumstances. Power nailers that have safety features that prevent their discharge and unsafe ways do not obsolete hammers.
          • TZubiri 1y ago
            https://tvtropes.org/pmwiki/pmwiki.php/Main/Metaphorgotten https://tvtropes.org/pmwiki/pmwiki.php/Main/Metaphorgotten
  • TZubiri 1y ago
    While I appreciate the sentiment of fighting against oversecure features. This is a great security feature. The Windows OS model started development in the 90s, before the internet or even malware was popular. Android started development around 2010 and was able to provide a security design that contemplated risks of malware and internet. In Windows installing malware compromises other applications, while in Android, your other apps are safe. In this news, this security mechanism fails. To denounce that the mechanism is completely useless is quite stupid, you just outed yourself as someone who doesn't have any security responsibilities and shouldn't have.
  • shkkmo 1y ago
    > Would that be a good hammer? They're called rubber mallets and they are useful in a number of situations where you want to > I would hope a malicious app I willingly installed will be able to behave maliciously. You should be able to install an app that has continuous access to your screen but that doesn't mean that continuous access to your screen is something you should have to grant to every piece of software that runs on your computer.
    • gdulli 1y ago
      You can hurt your thumb with a rubber mallet. Maybe the better metaphor would be kids' safety scissors which I guess represents the iPhone, but I'd still rather go with the Android (regular scissors) because I'm an adult and I'll take responsibility for the risks of using the more powerful tool.
      • akerl_ 1y ago
        Why are you speaking like having a secure device and a powerful device are exclusive options?
        • gdulli 1y ago
          Not being able to run arbitrary code that Apple hasn't given me permission to run doesn't meet my standard of powerful. I won't trade my freedom for a little extra security.
      • timothyduong 1y ago
        I think one can still build a product that has a level of guard rails without impacting usability. I also think iOS is more of an opinionated 'set of shears'. E.g. 'Right Hand only Scissors made from proprietary parts, made to only cut objects that 80% of scissor users need to cut' if we were to go down the road of analogies. Funnily enough Google Android is removing the ability for unsigned non-adb APKs. I would suggest your 'regular' scissors will be slightly bluntened in the upcoming Android 16 OS release.
• gnabgib 1y ago
  > Requires a victim to first install a malicious app on an Android phone or tablet As Raymond Chen/Old New Thing likes to say this rather requires being on the other side of this airtight hatchway. You can allow apps to do things on your device.
  • ranger_danger 1y ago
    https://0x0.st/XJZT.jpg https://0x0.st/XJZT.jpg
    • autoexec 1y ago
      That's a bit silly since seat belts were never designed or intended to protect against missiles. If a missile blows up your car that's no fault of your seat belt. You should expect android to prevent other apps from knowing what other apps you have installed and prevent them from accessing data they display though.
  • 0cf8612b2e1e 1y ago
    That the app does not require permissions is the notable bit here. I do not know the mobile system, but I thought apps were supposed to be firewalled from each other unless given explicit grants. The obvious joke, how long has Facebook been using this exploit?
    • OgsyedIE 1y ago
      Several preinstalled bloatware stores such as Galaxy Store, Moto apps and so forth will default to opt-in to automatically installing 'recommended apps and games' - essentially spyware garbage they get kickbacks from - in the background, plus several flagship phones now come with Temu preinstalled. The 90% of non technically-savvy Android users are 100% exposed to the OP exploit.
      • AmbroseBierce 1y ago
        The app needs to be opened by the user for the exploit to work, as seen in the video the researchers published, so the surface attack is big but not that big.
• dloy 1y ago
  And they can’t with iPhones?
  • SchemaLoad 1y ago
    iOS doesn't let apps silently screen record.
    • shkkmo 1y ago
      How are you sure? This isn't abusing some poorly secured screenshot API, this is a timing attack on the GPU rendering process and impacts a wide range of GPUs.
      • potwinkle 1y ago
        No. This isn't Spectre/Meltdown for GPUs, it takes advantage of SurfaceFlinger giving apps information on what's drawn behind them.
        • shkkmo 1y ago
          This attack measures the time needed to draw each pixel which varies due to graphical data compression. It is based on the "GPU.zip" vulnerability which was shown to affect most modern GPUs, including from Apple.
    • lostmsu 1y ago
      Neither does Android. This is a timing attack on rendering.
    • ajross 1y ago
      That's not what's happening here. The attack is exploiting a side channel of the rendering behavior, not reading the screen. There's no particular reason to believe that iOS is immune to something like this, though certainly no claim has been made. It's a new idea, it'll take a while for people to puzzle through the implications.
  • deleted 1y ago
• i386 1y ago
  Android supremacy at its finest. I would never recommend a family member buying one. The history of this kind of thing is long and keeps continuing to happen.
• ChrisArchitect 1y ago
  Source: https://www.pixnapping.com/ https://www.pixnapping.com/
  • ajross 1y ago
    This really needs to be the link. The article is phrased as if this was a zero day exploiting some kind of 2FA bug, but the actual meat is that it's a novel and really interesting new kind of attack vector (albeit not a particularly practical one) that no one had thought about before.
    • rs186 1y ago
      I would not say "no one had thought about before". Side channel attack is not a novel idea, just not used to find Android bugs like this.
      • ajross 1y ago
        > Side channel attack is not a novel idea Yes, but "side channel attack" isn't much of a description, is it? You can't just declare "I make a side channel attack!"[1], you need to invent one. In this case it turns out that the hardware rendering of the zoom animation in the blur effect of stacked activities on the screen left crumbs that can be detected in the alien context. I certainly didn't know that. Did you know that? I don't think anyone knew that! It's "novel". [1] Shades of Michael Scott declaring bankruptcy.
  • cookiengineer 1y ago
    Quote: > Google has attempted to patch Pixnapping by limiting the number of activities an app can invoke blur on. However, we discovered a workaround to make Pixnapping work despite this patch. The workaround is still under embargo. Great, google's security policy ending up being a zeroday. Exactly as denied and exactly as predicted by the community. Also, this is the direct paper link: https://www.pixnapping.com/pixnapping.pdf https://www.pixnapping.com/pixnapping.pdf
    • 1y ago
• lostmsu 1y ago
  TL;DR; This is a timing attack on rendering that allows capture of screen data.
• hollow-moe 1y ago
  Don't worry you won't be able to install the bad application in the first place thanks to the new ID backed app signature.
• lll-o-lll 1y ago
  This is a really interesting new side channel attack. One I had never considered before; it’s like rowhammer but for the screen. Clever. Also evil. Clever and evil.
  • baobun 1y ago
    There should be a new, stronger word for these kinds of attacks. Like clevevil, or clevil. Yes, pixnapping is clevil. We should strive for the opposite: livelc.
  • deleted 1y ago
    [deleted]
• pimlottc 1y ago
  I'm stuck on the part of the attack where the malicious app opens another app: > 2. Attacker app opens Google Authenticator's main activity > 3. Attacker app opens a stack of activities to include graphical operations on pixels displayed by Google Authenticator's main activity Android allows apps to call other apps? While remaining in the foreground? How does that work? I don't think iOS allows this.
  • deleted 1y ago
    [deleted]
  • jhancock 1y ago
    What I got from the article is the malicious app could read the SMS or email which may contain a 2FA code.
  • magicalhippo 1y ago
    > Android allows apps to call other apps? While remaining in the foreground? How does that work? From the paper: Recall from Section 2.1 that when a caller activity sends an intent to a callee activity, Android moves the callee activity to the foreground (along with its task’s back stack if android:-launchMode="singleTask") and moves the caller activity to the background. However, despite no longer being in the foreground, the caller activity is still allowed to send intents that start additional activities from the background. For example, the caller activity can send another intent to launch a second callee activity. In this case, the second callee moves to the foreground, while the first callee is moved to the background. Further, SurfaceFlinger treats the window of the second callee as being overlaid in front of the window of the first callee. In our framework, the attacker app leverages this behavior to layer a stack of semi-transparent activities in front of a newly launched victim activity. In the following, we describe how the attacker uses this stack and SurfaceFlinger’s APIs to isolate, enlarge, and transmit individual pixels from the victim activity.
    • crowbahr 1y ago
      So kinda like Strandhogg and Tap jacking had a horrible security breach baby
• aussieguy1234 1y ago
  More accurate title: "There's a new trojan out for android. Like any trojan, it gives the attacker access to things they shouldn't have access to"
  • autoexec 1y ago
    The issue isn't that a trojan gives the attacker access to things they shouldn't have access to, the problem is that android gives the trojan access to things it shouldn't so that the data it collects can be passed back to the attacker.
• ufmace 1y ago
  It's a cool and interesting type of attack, but I really don't care for the breathless clickbait headlines that are sourced to a few security researchers demonstrating an attack in a lab, that has already been patched against and has never been seen in the wild.
  • hovav 1y ago
    > has already been patched against ... has not been (effectively) patched against, as it happens. Maybe in December!
  • magicalhippo 1y ago
    Good thing every Android phone gets fresh updates all the time then.
    • conorcleary 1y ago
      with detailed changelogs!
      • Terr_ 1y ago
        "Security and Stability Improvements", part 413.
  • rs186 1y ago
    In Android world, there is not such thing as "has been patched". It is always A complex situation with all different OEMs, devices and versions. The patch was committed about 3 months ago, possibly available to OEMs as binary earlier, but devices are probably just receiving these patches. I bet at least half of all affected Android devices in the world have not got the patch yet if I am optimistic. It's probably near 80-90%.
• rkagerer 1y ago
  Could this be mitigated by introducing some random timing jitter during rendering?
• nh2 1y ago
  Curious if the same technique would also work on Wayland, given one of its design goals is higher cross-app security compared to Xorg.
  • coppsilgold 1y ago
    This attack seems to be explicitly exploiting the Android rendering pipeline through a side-channel. Wayland, once hardened with security-context doesn't directly expose anything worrying (clipboard stealing is possible but would require window focus or the generation of a window which grabs focus). It remains to be seen if there are side-channels hiding somewhere in it or in the various GPU stacks.
• askariwa 1y ago
  Just use the Google Authenticator's "Privacy Screen" which requires a PIN, pattern, or biometric verification to open the app. This renders this hack unusable ;-)
  • nurettin 1y ago
    Unless you social engineer to export the auth code as QR, take a screenshot, extract the secret key which is pretty much in plain bytes and use it to generate TOTP.
• jeffrallen 1y ago
  Tldr: this is a timing-based side channel in GPUs allowing and attacker to read pixels from the screen without special privs. Side channels are why we can't have nice things.
• dataflow 1y ago
  tl;dr: This hack is "using a timing attack exploiting the GPU's graphical data compression to try finding out the color of the pixels."
• rs186 1y ago
  > Does Google plan to patch these APIs? > > Google has attempted to patch Pixnapping by limiting the number of activities an app can invoke blur on. However, we discovered a workaround to make Pixnapping work despite this patch. The workaround is still under embargo. Can I assume this is being exploited in the wild? Some black hats must be smart enough to figure out the workaround on their own.