TikTok faces growing national security concerns: "It's not just the collection or theft of that data"

With more than 1 billion monthly users worldwide, TikTok has transfixed many users with a platform that seems to know who they are. But critics say TikTok might know too much. 

The popular social media app tracks its users' likes, dislikes and personal information, including email addresses, phone numbers and WiFi networks.

Gizmodo senior technology reporter Thomas Germain showed CBS News how TikTok sweeps up user data, including access to users' contacts.