I stopped trusting calling line id (CLI) some years ago. Just because my mobile tells me it’s the bank calling, I don’t believe it. It seems 5G won’t improve things…:
[…] Every tested network was vulnerable to denial of service against network equipment, which would result in legitimate internet users not being able to connect to the internet. Unlike DoS attacks targeted against specific users, denial of service against network equipment means loss of connection for a large number of users and could be especially dangerous for 5G networks because subscribers will also include IoT devices such as industrial equipment, smart homes, and city infrastructure.
Through the GTP protocol, networks were also vulnerable to impersonation attacks, where a criminal assumes the identity of a subscriber to get authorized access to online services and bypass two factor authentication, and fraud, where fraudsters perform mobile traffic drain for fake roamers and make the operator pay for it.