One the of UK's biggest mobile operators, Three mobile , has become the latest victim of a massive data breach that reportedly left the personal information and contact details of 6 Million of its customers exposed.

The company admitted the data breach, saying that computer hackers gained access to a Three Mobile customer phone upgrade database containing the account details of nearly 6 Million customers.

According to multiple British media reports citing both Three and the National Crime Agency (NCA), the computer hackers used an employee login to gain entry into its database.
 
The stolen data includes customer names, addresses, phone numbers and dates of birth, which is then used to carry out mobile phone fraud.

The company has not yet confirmed the total number of users' affected by the breach, though it assured its customers that no payment data, including bank account numbers and card numbers, has been accessed.

According to Three, the hackers had stolen the database to use the stolen personal details to find customers eligible for handset upgrade, placing orders for the new phones, intercepting the parcels as they arrived, and then reselling them for a profit.

To date, Three has confirmed around 400 cases in which fraudsters had stolen high-value handsets through burglaries and 8 devices have already been illegally obtained through the upgrade activity.