UpGuard researchers discovered 1.7 terabytes of confidential data including login details for administrative platforms.

MTS (Mobile TeleSystems), Russia’s most popular telecommunications operator, was affected by the breach together with Nokia which is responsible for MTS’s network maintenance.

The exposed information on telecoms used for surveillance became public by a Nokia employee who owned an unprotected backup drive where the data was discovered.

Nokia also monitors MTS’s compliance with SORM – Russian surveillance system which creates a peculiar connection between authorities and the operator’s customers by giving access to private calls and messages.

The flash drive containing the sensitive documents was inserted by the employee into his personal computer. The USB and computer appeared to be freely accessible online.

There was data concerning a large project designed to install devices for sanctioned interception of people’s conversations.

The investigation is ongoing.