Shopping app Temu is “dangerous malware,” spying on your texts, lawsuit claims

Nemeski@lemm.ee to Technology@lemmy.world – 851 points –
Shopping app Temu is “dangerous malware,” spying on your texts, lawsuit claims
arstechnica.com
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I'm sure Temu collects all information you put into the app and your behaviour in it, but this guy is making some very bold claims about things that just aren't possible unless Temu is packing some serious 0-days.

For example he says the app is collecting your fingerprint data. How would that even happen? Apps don't have access to fingerprint data, because the operating system just reports to the app "a valid fingerprint was scanned" or "an unknown fingerprint was scanned", and the actual fingerprint never goes anywhere. Is Temu doing an undetected root/jailbreak, then installing custom drivers for the fingerprint sensor to change how it works?

And this is just one claim. It's just full of bullshit. To do everything listed there it would have to do multiple major exploits that are on state-actor level and wouldn't be wasted on such trivial purpose. Because now that's it's "revealed", Google and Apple would patch them immediately.

But there is nothing to patch, because most of the claims here are just bullshit, with no technical proof whatsoever.

Here's the actual relevant part

These are security risks to be sure, and while these permissions are (mostly) on the surface, possibly defensible, together they do clearly represent an app trying to gather all of the data that it can.

However, a lot of info from this report is overblown. For example code compilation is sketchy to be sure, but without a privilege escalation attack, it can't do anything the app couldn't do with an update.

Also, there's some weird language in the report, like counting the green security issues in other apps (like tiktok) as if they were also a problem, despite the image showing that green here means it doesn't present that particular risk.

All of this to say, if you have temu, probably uninstall it. It's clearly collecting all the data it can get.

But it's unlikely to be the immediate threat that will have China taking over your phone like this report implies.

This infographic is really helpful. Stuff like this makes me relieved I use the majority of services in a browser, rather than native apps

I'm blown away by how many people use apps when they don't have to. There's a reason companies are always trying to get you to download their app, and it's so they can put their software on your phone and harvest more of your data.

Exactly why I use browser and not apps, too. and if they try to strongarm me with better prices or degraded services, I just stop using them all together.

Yup. I used to watch TikTok’s sent to me. Now I can’t. They want me to use their app. LOL. Nah.

It's why I stopped using Reddit on mobile lol. No, I don't want to download your official app, and no you making it so I need it to access NSFW stuff will convince me to.

Same with X/Twitter. I hate when people put information in those now because you can't read more than one at a time in some reply to self thread on there without downloading the app. Especially when it's important news or on the ground reporting. Screw that. All those reporters need to use mastadon.

That.. is not a study by anyone who knows what they are talking about. It also does not mention fingerprints at all.

They seem to believe that the app can use permissions undeclared in the manifest file because they obviously think it's only for the store to show the permissions to the user. Android will not actually allow an app to use undeclared permissions. The most rational explanation is the codebase is shared with different version of the app (possibly not released) that had different manifests.

It also makes a big deal of checking if running as root. That is not evidence of having an escalation exploit. If they have an ability to get root before running the app why would they need to use the app to exploit it? They could just do whatever they wanted and avoid leaving traces in the app. Though I doubt they would root phones to just brick them. It's the kind of mischief you would expect from a kid writing viruses, not an intelligence agency or criminal enterprise.

Users who root their own phones are very unlikely to run temu as root. In fact a lot of apps related to shopping or banking try to detect root to refuse to work as your system is unsafely. In any case it's a very niche group to target.

To keep things short, that 'study' does not really look credible or written by actual experts.

The analysis shows it's spyware, which I don't question. But it's spyware in the bounds of Android security, doesn't hack anything, doesn't have access to anything it shouldn't, and uses normal Android permissions that you have to grant for it to have access to the data.

For example the article mentions it's making screenshots, but doesn't mention that it's only screenshots of itself. It can never see your other apps or access any of your data outside of it that you didn't give it permission to access.

Don't get me wrong, it's very bad and seems to siphon off any data it can get it's hands on. But it doesn't bypass any security, and many claims in the article are sensational and don't appear in the Grizzly report.

I agree on the sensationalism in the article.

Still sounds like shitty company doing shitty things

That is not entirely correct. The reported found the app using permissions that are not covered by the manifest. It also found the app being capable to execute arbitrary code send by temu. So it cannot be clearly answered if the app can utilize these permissions or not. Obviously they would not ship such an exploit with the app directly.

The reported found the app using permissions that are not covered by the manifest.

It didn't found them using them, it's an important distinction. It found code referring to permissions that are not covered by the Manifest file. If that code was ran, the app would crash, because Android won't let an app request and use a permission not in the Manifest file. The Manifest file is not an informational overview, it's the mechanism through which apps can declare permissions that they want Android to allow them to request. If it's not in the Manifest, then it's not possible to use. It's not unusual to have a bunch of libraries in an app that have functionality you don't use, and so don't declare the required permissions in the Manifest, because you don't use them.

It also found the app being capable to execute arbitrary code send by temu.

Yeah, which is shady, but again, there is nothing to indicate that code can go around any security and do any of the sensational things the article claims.

The Grizzly reports shows how the app tricks you into granting permissions that it shouldn't need, very shady stuff. But it also shows they don't have a magical way of going around the permissions. The user has to actually grant them.

Do you know if there people who have gone this far analysing the TikTok and WeChat apps?

Yeah, I don't like Temu, and I'm sure the app is a privacy nightmare, but these claims don't seem right. If it's true, I'd like to see someone else verify it.

Haven't read the article because I'm not interested in an app I don't use, but does it mean browser fingerprint? Because that's slang for the fonts/cookies/user-data of your browser, and lots of apps have access to that.

Wouldn't the phone have to have your fingerprint stored in order to compare it to the one scanned?

Yes, the phone does, but that data is protected in the hardware and never sent to the software, the hardware basically just sends ok / not ok. It's not impossible to hack in theory, nothing is, but it would be a very major security exploit in itself that would deserve a bunch of articles on it's own. And would likely be device specific vulnerability, not something an app just does wherever installed.

Pretty sure this is not true. That's how apple's fingerprint scanners work. On android the fingerprint data is stored either in the tpm or a part of the storage encrypted by it.

Yeah, so the app never sees it. What are you disagreeing with?

I just corrected that, can't I without disagreeing?

I mean that I don't know what part of my comment is "not true". I welcome corrections, I just don't see what is being corrected here.

It doesn't send a yes/no signal it sends the fingerprint to be compared to the stored one