TikTok is well-known for using vulnerabilities to access more personally identifying data than it should from users [0], such as MAC addresses [1] and IMEI numbers for the SIM cards.

[0]: https://theforestscout.com/35101/in-lfhs/tiktok-app-comes-wi...

[1]: https://www.wsj.com/articles/tiktok-tracked-user-data-using-...