it's not for you:
In 2018, the Cybereason Nocturnus team identified an advanced, persistent attack targeting global telecommunications providers carried out by a threat actor using tools and techniques commonly associated with the Chinese-affiliated threat actor APT10. This multi-wave attacks focused on obtaining data of specific, high-value targets and resulted in a complete takeover of the network.
https://www.cybereason.com/blog/operation-soft-cell-a-worldwide-campaign-against-telecommunications-providers?ftag=MSFd61514f