News for hackers. Stuff that matters.
Re:Privacy analysis of Tiktok’s app and website by hombre_fatal on Friday December 06, 2019 @03:48PM (#21725837)
99% of websites we visit do not need canvas or sound. And the few websites that do can explain why you should click "Allow" when they prompt you for access.

What's a charitable reason that stops even a supposedly privacy-concerned niche browser like Brave from implementing opt-ins for these things?

I suppose one reason is that you would immediately unleash opt-in spam on your users that don't know what these pop-ups mean since so many major websites use these hacks, so the average user is just going to be conditioned to mindlessly click "Allow All" every time they pop up like UAC on Windows Vista, punishing the average person while doing nothing to enhance their security.

Doesn't help that legislators are absolutely clueless here. For example, demonizing cookies when cookies are the most fair and transparent way to implement tracking, and leading to the first wave of pointless opt-in spam that plagues the internet. I'd rather they leave the internet alone and for browser vendors to step up for us.

Of course, the problem also includes native apps like in TFA. I'm just more optimistic about clients that run in web browsers.

Re:Privacy analysis of Tiktok’s app and website by iudqnolq on Saturday December 07, 2019 @01:39AM (#21728873)
In Firefox, setting privacy.resistFingerprinting = true in about:config fixes the canvas leak and possibly the audio leak. It's part of a push to bring into Firefox privacy features from the TOR project.

https://wiki.mozilla.org/Security/Fingerprinting

Re:Privacy analysis of Tiktok’s app and website by stinos on Saturday December 07, 2019 @04:09AM (#21729265)
I really want to do this, but last time I checked it also leads to FF sending UTC time back to sites (or something like that), resulting in showing non-local time for your own and other interactions on pretty much all sites like github/slack/... Fairly annoying. I hope this becomes a separate setting at one point.
Re:Privacy analysis of Tiktok’s app and website by arjunbajaj on Sunday December 08, 2019 @04:33AM (#21735079)
I enabled it and Todoist would show me a dialog on every page reload to set my timezone to UTC. After I realized that resistFingerprinting was causing it, I had to disable it.

It would be nice if the settings inside resistFingerprinting were configurable. I understand that the point of it is to make every browser look the same to analytics engine, but having timezones and zoom levels reset is not the best thing.

Re:Privacy analysis of Tiktok’s app and website by jmiserez on Sunday December 22, 2019 @04:21AM (#21856115)
Or file a bug report with Todoist. Showing a dialog on every page is not very user friendly of them.
Re:Privacy analysis of Tiktok’s app and website by animesh on Saturday December 07, 2019 @06:16AM (#21729663)
I don't know about fixing canvas and audioleak, but it reset browser zoom to 100% on every load of any website say HN. This is pretty annoying.
Re:Privacy analysis of Tiktok’s app and website by iudqnolq on Saturday December 07, 2019 @10:44AM (#21730812)
Re:Privacy analysis of Tiktok’s app and website by sgn on Saturday December 07, 2019 @08:05AM (#21730065)
Firefox 58+ blocks canvas by default. We don't need to change about:config for Canvas tracking.

Not sure about the status of AudioContext tracking, though.

Re:Privacy analysis of Tiktok’s app and website by iudqnolq on Saturday December 07, 2019 @10:42AM (#21730805)
Re:Privacy analysis of Tiktok’s app and website by stiray on Saturday December 07, 2019 @04:33AM (#21729324)
Ok, how to fix fingerprinting:

- for web, stop using chrome, install firefox (or firefox mobile) and in about:config set privacy.resistFingerprinting on true then add following addons:

https://addons.mozilla.org/en-US/android/addon/canvas-finger...

https://addons.mozilla.org/en-US/android/addon/audioctx-fing...

https://addons.mozilla.org/en-US/android/addon/webgl-fingerp...

https://addons.mozilla.org/en-US/android/addon/font-fingerpr...

They will not only prevent fingerprints but also screw with the data (add random noise to audio/webgl sample, return random fonts,...).

- the most important rule, don't use applications like tiktok, fb,.. if your phone is not rooted, with xprivacylua (https://github.com/M66B/XPrivacyLua, for added kicks https://github.com/M66B/NetGuard) installed and you have basic understanding what you allow there (disallow everything for new apps and work permissions one by one). The sole purpose of those apps and their bussiness model is to steal your data. This is most sane advice I can give, sorry :(

Voila. Solved.

Those methods of fingerprinting are few years old and well known.

Re:Privacy analysis of Tiktok’s app and website by pferde on Saturday December 07, 2019 @12:07PM (#21731282)
Thanks, these look awesome - simple, yet powerful.
Re:Privacy analysis of Tiktok’s app and website by stiray on Sunday December 08, 2019 @06:31AM (#21735402)
Yes, and doing exactly what they should be doing nothing more and nothing less. I love small utilities :)
Re:Privacy analysis of Tiktok’s app and website by dylz on Friday December 06, 2019 @04:37PM (#21726223)
> What's a charitable reason that stops even a supposedly privacy-concerned niche browser like Brave from implementing opt-ins for these things?

In my experience, blocking these everywhere globally as a default will result in being banned from websites, trigger bullshit "fraud" invasive analytics, and all sorts of obnoxious fail-closed problems by invasive trackers.

You will also be banned from most Distil-hosted sites for refusing to enable WebGL or return a canvas fingerprint. Ticketmaster, etc.

Re:Privacy analysis of Tiktok’s app and website by kbenson on Friday December 06, 2019 @07:59PM (#21727698)
If a large enough chunk of people do it, then it becomes unfeasible to block them all. If Safari, Firefox and Internet Explorer all implemented a block, it doesn't really matter that Chrome doesn't. That's ~30% of browsing traffic, and no sane company with a large web presence is going to throw away 30% of their traffic.
Re:Privacy analysis of Tiktok’s app and website by tempguy9999 on Saturday December 07, 2019 @06:21AM (#21729676)
Agreed! There's a lot of moaning about how things should be better.

Be the change you want to see. Do it. I'm always amazed at how people will complain but then let themselves be pushed around. I wonder how many people reading this article will change their or their browser's behaviour afterwards. Very few I guess.

Re:Privacy analysis of Tiktok’s app and website by munk-a on Friday December 06, 2019 @05:09PM (#21726492)
Sounds great - especially if chrome could roll out default blocking of it.

The EU (via GDPR) made a collective decision to disallow invasive privacy, if TickTock's response to that is to ban everyone in the EU and entirely lose the market that sounds good to me - teenagers will complain and people will shrug.

Re:Privacy analysis of Tiktok’s app and website by dylz on Friday December 06, 2019 @05:15PM (#21726535)
This is being done in EU anyway. IIRC I've seen several third party vendorssay that this type of tracking is legal under GDPR to justify 'anti fraud activities' like tracking users and sharing access to their data with other paying customers.

I personally have EasyPrivacy enabled on uBlock (because these tracking scripts using canvas, webgl, etc spin up my GPU and absolutely shit all over my battery life) but they are getting more and more aggressive with first-party CNAMEs, shipping a list of dozens or hundreds of hostnames to try progressively if any are blocked (and probably honestly risk score you higher for "trying to evade them" even though it's a default uBlock list).

I think it's honestly rather stupid, and I am not a fan of hearing my fans spin up for no reason accessing an otherwise plain website while it tries to open media players, try video elements, draw to canvas, download several megabytes of obfuscated garbage to evaluate.

Re:Privacy analysis of Tiktok’s app and website by munk-a on Friday December 06, 2019 @05:20PM (#21726585)
I've worked in anti-fraud software and it isn't necessary. Fingerprinting is extremely convenient and sales loves it, but I would hope that necessity could be broken down by reasoned arguments in the EU - I'm outside of the EU and not familiar enough with GDPR but there are a number of clear and accessible counters to that point - especially if payment is involved. If payment comes into play then fingerprinting becomes irrelevant as anyone making a payment can be trusted up to the level of that payment and that payment method tied to their actions.
Re:Privacy analysis of Tiktok’s app and website by shrimp_emoji on Saturday December 07, 2019 @09:38PM (#21734043)
Perhaps more egregiously, using a VPN gets you auto-banned from some Battlefield 4 servers. D:
Re:Privacy analysis of Tiktok’s app and website by ehsankia on Friday December 06, 2019 @07:12PM (#21727437)
> And the few websites that do can explain why you should click "Allow" when they prompt you for access.

You missed it, this doesn't require an Allow, because it's not actually accessing the microphone. It's using the audio APIs to generate a waveform, and depending on your computer/DSP, the waveform will be slightly different. It's not using any of your computers sensors

https://news.ycombinator.com/item?id=21436414

Re:Privacy analysis of Tiktok’s app and website by kbenson on Friday December 06, 2019 @07:55PM (#21727682)
> You missed it, this doesn't require an Allow, because it's not actually accessing the microphone.

Presumably, without an allow the API doesn't function at all, so it works perfectly well. When denied access, the API should either not exist, or (more appropriately) just return errors.

Re:Privacy analysis of Tiktok’s app and website by shakna on Saturday December 07, 2019 @01:43AM (#21728878)
> Presumably, without an allow the API doesn't function at all

An incorrect presumption. The API works perfectly fine without the need for permissions.

This is not a new technique. There's a decent write up here [0].

Permissions are only required to play to the actual device, or record from the actual device. Recording from nothing and not playing is allowed.

[0] https://iq.opengenus.org/audio-fingerprinting/

Re:Privacy analysis of Tiktok’s app and website by kbenson on Saturday December 07, 2019 @02:48AM (#21729040)
We're talking about a theoretical situation where we gate the canvas and audio api behind a permission prompt. My "presumably" is about how that would be theoretically implemented.
Re:Privacy analysis of Tiktok’s app and website by ehsankia on Monday December 09, 2019 @06:58AM (#21741917)
Except prompt spam is a real issue too. Very quickly you can end up like Windows' UAC that basically trains people to blindly click "yes" on any dialog they see. Putting a permission prompt for every tiny little thing a browser can do isn't a good experience for the user, and most people will have no clue what "allow access to canvas/audio api" means.
Re:Privacy analysis of Tiktok’s app and website by kbenson on Monday December 09, 2019 @12:47PM (#21744664)
Except that with a prompt for a specific API, you can get specific on when it's appropriate. E.g.

"This website has asked for permission to use the Audio API. If they aren't actively doing audio processing, this may be an attempt to identify and track you. If you haven't been presented by the site with a good reason why to allow this access, and it's not immediately obvious (such as for a music service), consider whether you want them to have access."

This accomplishes a few things. First, it's very clear about the implications and when it's obvious it should be allowed. Second, it gently suggests the default behavior for people should be to deny unless needed. Thirdly, it communicates to sites (through users the appropriate way to ask for permissions if hey have a legitimate reason, which is to let users know why they need access. Lastly, if sites lie to users about why they need access, they can be called out on that. People don't like being lied to.

Re:Privacy analysis of Tiktok’s app and website by ehsankia on Monday December 09, 2019 @02:02PM (#21745296)
Now imagine getting 10 of these, as a user who has no idea what those words mean, nor care, because you just want to see the latest meme on Facebook, and you just blindly press Allow on everything and quickly become desensitized to all prompts.
Re:Privacy analysis of Tiktok’s app and website by shakna on Saturday December 07, 2019 @03:15AM (#21729116)
Why would gating the API behind the Permissions API change what is currently considered permission by the Browser?

That'd require rewriting the API itself.

Re:Privacy analysis of Tiktok’s app and website by kbenson on Saturday December 07, 2019 @04:05AM (#21729254)
Gating the API behind a permissions dialog or permission setting. The difference being that an end site either uses it and gets valid data (because the user allowed it, the default without a dialog today), or gets errors letting them know the data can't be relied upon.

If you visit a random internet site and get a prompt for the audio API are you going to allow it? Probably not, especially if you think it's just so the site can be obnoxious with sounds or listen to you.

The canvas api might be a little more likely to be allowed by the average person, but enough might disallow or ask about it that sites that have a valid use for it will put up a banner noting why it's important, making sites using it for tracking stand out all the more.

The bottom line is that we're coming to an understanding (well, it's been known for years) that each additional browser feature has downsides, so making them enabled by default has repercussions.

Re:Privacy analysis of Tiktok’s app and website by shakna on Saturday December 07, 2019 @04:15AM (#21729279)
> Gating the API behind a permissions dialog or permission setting.

Those dialogs and settings are controlled by the Permissions API today.

> If you visit a random internet site and get a prompt for the audio API are you going to allow it? Probably not, especially if you think it's just so the site can be obnoxious with sounds or listen to you.

You and I might disable it. Overwhelmingly, the majority of the public click "enable" or "yes" on permission pop-ups. And tend to make sure "enable forever" is ticked.

> The bottom line is that we're coming to an understanding (well, it's been known for years) that each additional browser feature has downsides, so making them enabled by default has repercussions.

I don't disagree. The problem here is that the permission model itself has been broken, and won't be repaired because of backwards compatibility, and a lack of incentive.

Re:Privacy analysis of Tiktok’s app and website by qxnqd on Friday December 06, 2019 @04:11PM (#21726026)
Brave blocks cross-site canvas by default under their "Device recognition" option. You can also block first-party canvas access.
Re:Privacy analysis of Tiktok’s app and website by bscphil on Sunday December 08, 2019 @01:12AM (#21734586)
This is a genuinely great idea. Other stuff like recording audio, looking at your location, and even annoyances like sending you notifications all require a permission request that appears in the browser chrome. Why doesn't Firefox put other features that impact privacy behind the same barrier?
Re:Privacy analysis of Tiktok’s app and website by thinkloop on Friday December 06, 2019 @11:41PM (#21728513)
> Doesn't help that legislators are absolutely clueless here.

You're a world-leading computerist and you had no clue either (nor I), how in the world are legislators supposed to do this. It's a fundamental problem. And once it's finally legislated the sme's are already on the next thing.

Re:Privacy analysis of Tiktok’s app and website by Angeo34 on Sunday December 08, 2019 @03:15PM (#21738005)
Brave is just snake oil. They couldn't ever implement true canvas or audio protection or prevent font or window decoration fingerprinting even if they wanted.

If you want that stuff you use Firefox and enable resistFingerprinting its the only possible way

Re:Privacy analysis of Tiktok’s app and website by varenc on Saturday December 07, 2019 @03:09AM (#21729097)
Google's ReCAPTCHA uses the same canvas fingerprinting trick.