Penetrum_TikTok_Security_Analysis_whitepaper
you've been warned
you've been warned
Edit: Please read to avoid confusion:
I'm getting together the data now and enlisted the help of my colleagues who were also involved in the RE process. We'll be publishing data here over the next few days: https://www.reddit.com/r/tiktok_reversing/. I invite any security folk who have the time to post what they've got as well - known domains and ip addresses for sysadmins to filter on, etc. I understand the app has changed quite a bit in recent versions, so my data won't be up to date.
I understand there's a lot of attention on this post right now, but please be patient.
So I can personally weigh in on this. I reverse-engineered the app, and feel confident in stating that I have a very strong understanding for how the app operates (or at least operated as of a few months ago).
TikTok is a data collection service that is thinly-veiled as a social network. If there is an API to get information on you, your contacts, or your device... well, they're using it.
On top of all of the above, they weren't even using HTTPS for the longest time. They leaked users' email addresses in their HTTP REST API, as well as their secondary emails used for password resets. Don't forget about users' real names and birthdays, too. It was allllll publicly viewable a few months ago if you MITM'd the application.
They provide users with a taste of "virality" to entice them to stay on the platform. Your first TikTok post will likely garner quite a bit of likes, regardless of how good it is.. assuming you get past the initial moderation queue if thats still a thing. Most users end up chasing the dragon. Oh, there's also a ton of creepy old men who have direct access to children on the app, and I've personally seen (and reported) some really suspect stuff. 40-50 year old men getting 8-10 year old girls to do "duets" with them with sexually suggestive songs. Those videos are posted publicly. TikTok has direct messaging functionality.
Here's the thing though.. they don't want you to know how much information they're collecting on you, and the security implications of all of that data in one place, en masse, are fukking huge. They encrypt all of the analytics requests with an algorithm that changes with every update (at the very least the keys change) just so you can't see what they're doing. They also made it so you cannot use the app at all if you block communication to their analytics host off at the DNS-level.
For what it's worth I've reversed the Instagram, Facebook, Reddit, and Twitter apps. They don't collect anywhere near the same amount of data that TikTok does, and they sure as hell aren't outright trying to hide exactly whats being sent like TikTok is. It's like comparing a cup of water to the ocean - they just don't compare.
tl;dr; I'm a nerd who figures out how apps work for a job. Calling it an advertising platform is an understatement. TikTok is essentially malware that is targeting children. Don't use TikTok. Don't let your friends and family use it.
I'm getting together the data now and enlisted the help of my colleagues who were also involved in the RE process. We'll be publishing data here over the next few days: https://www.reddit.com/r/tiktok_reversing/. I invite any security folk who have the time to post what they've got as well - known domains and ip addresses for sysadmins to filter on, etc. I understand the app has changed quite a bit in recent versions, so my data won't be up to date.
I understand there's a lot of attention on this post right now, but please be patient.
So I can personally weigh in on this. I reverse-engineered the app, and feel confident in stating that I have a very strong understanding for how the app operates (or at least operated as of a few months ago).
TikTok is a data collection service that is thinly-veiled as a social network. If there is an API to get information on you, your contacts, or your device... well, they're using it.
- Phone hardware (cpu type, number of course, hardware ids, screen dimensions, dpi, memory usage, disk space, etc)
- Other apps you have installed (I've even seen some I've deleted show up in their analytics payload - maybe using as cached value?)
- Everything network-related (ip, local ip, router mac, your mac, wifi access point name)
- Whether or not you're rooted/jailbroken
- Some variants of the app had GPS pinging enabled at the time, roughly once every 30 seconds - this is enabled by default if you ever location-tag a post IIRC
- They set up a local proxy server on your device for "transcoding media", but that can be abused very easily as it has zero authentication
On top of all of the above, they weren't even using HTTPS for the longest time. They leaked users' email addresses in their HTTP REST API, as well as their secondary emails used for password resets. Don't forget about users' real names and birthdays, too. It was allllll publicly viewable a few months ago if you MITM'd the application.
They provide users with a taste of "virality" to entice them to stay on the platform. Your first TikTok post will likely garner quite a bit of likes, regardless of how good it is.. assuming you get past the initial moderation queue if thats still a thing. Most users end up chasing the dragon. Oh, there's also a ton of creepy old men who have direct access to children on the app, and I've personally seen (and reported) some really suspect stuff. 40-50 year old men getting 8-10 year old girls to do "duets" with them with sexually suggestive songs. Those videos are posted publicly. TikTok has direct messaging functionality.
Here's the thing though.. they don't want you to know how much information they're collecting on you, and the security implications of all of that data in one place, en masse, are fukking huge. They encrypt all of the analytics requests with an algorithm that changes with every update (at the very least the keys change) just so you can't see what they're doing. They also made it so you cannot use the app at all if you block communication to their analytics host off at the DNS-level.
For what it's worth I've reversed the Instagram, Facebook, Reddit, and Twitter apps. They don't collect anywhere near the same amount of data that TikTok does, and they sure as hell aren't outright trying to hide exactly whats being sent like TikTok is. It's like comparing a cup of water to the ocean - they just don't compare.
tl;dr; I'm a nerd who figures out how apps work for a job. Calling it an advertising platform is an understatement. TikTok is essentially malware that is targeting children. Don't use TikTok. Don't let your friends and family use it.
I'm all for it
