https://www.bleepingcomputer.com/news/security/chinese-hackers-breached-t-mobiles-routers-to-scope-out-network/

T-Mobile says the Chinese "Salt Typhoon" hackers who recently compromised its systems as part of a series of telecom breaches first hacked into some of its routers to explore ways to navigate laterally through the network.

However, the company says its engineers blocked the threat actors before they could spread further on the network and access customer information.