A New Data Breach May Have Hit T-Mobile, 90GB of User Data Exposed

tmo has many of their services ran by external vendors, vendors have access into tmo for provisioning and some customer records. iphone provisioning and the Caller ID directory services are 2 that have been rumored as culprits. Once you have access to the internal support systems, a bad employee at a vendor can pull much data.

ATT has less of that, att tends to have employees run the services, they still buy from a vendor, but they have employees run it. But employees have been arrested for access data for cartels.