Good thing every Android phone gets fresh updates all the time then.

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%.

> has already been patched against

... has not been (effectively) patched against, as it happens. Maybe in December!

> 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.

What I got from the article is the malicious app could read the SMS or email which may contain a 2FA code.

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?

Yes, just because a popular blog about a infamously insecure operating system shrugged off certain classes of security problems as “you’re holding it wrong” two decades ago, OS security should be held to the same standard as that piece of shit OS forever. Nothing to see here.

Edit: IIRC the original argument was more reasonable, but it has since been abused in all kinds of situations to make low effort putdowns, like this one.

It can happen quickly. The app itself might be legit, but it may be based in a SDK which is either malicious or compromised.

> The new attack, named Pixnapping by the team of academic researchers who devised it, requires a victim to first install a malicious app on an Android phone or tablet.

I think it speaks about the security of Android that this makes the news. Coming from Windows, Android always felt as a MUCH more secure Operating System, not just a similar quality Operating System with touch controls and support for smaller hardware.

Raymond Chen's saying is about trust boundaries. That if there's no trust boundary defined, or if a defined boundary is being crossed with consent, then it is unsound to claim there being a security vulnerability (which would be a behavior that allows for crossing a trust boundary without consent).

This doesn't apply in this case, as (usermode apps') screen capturing does require permission, and applications can specifically opt-out from being captured by apps even with that permission, which Google Authenticator does have set. So a trust boundary is being violated, therefore this is a legitimate security issue by his logic.

It also requires that whatever information the attacker is looking for has been displayed on the screen, so for example my banking app (like most banking apps I guess) masks my 4 digit passcode with asterisks so it is likely safe from this specific attack

PD: I just checked and it also doesn't change the color of the pressed keys or any other visual feedback that an attacker might use.

https://0x0.st/XJZT.jpg

In other news, there are substances in the household that are so dangerous that it can can kill you.

First it requires the user take buckets of ammonia and bleach and mix them together.

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.

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

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.

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.

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.

> requires no [Android] permissions

I think this is the part people are upset about

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.

> Would you buy a hammer that can't ever hurt your thumb?

Yes.

> 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.

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.

iOS doesn't let apps silently screen record.

You can't put one app on top of another, so that mitigates at least the 1st stage of this kind of attack.