S 2.27 Dispensing with remote maintenance of the PBX

Initiation responsibility: Head of IT Section; IT Security Management; PBX officer

Implementation responsibility: -

Dispensing with remote maintenance is an effective measure to prevent external persons from manipulating the PBX installation configuration. For individual installations and small networks of interconnected installations with short spatial distances between their individual members, this approach is expedient also for economic reasons.

Advantage: As opposed to all other measures listed in Part I, Chapter 8.1 Telecommunications System (Private Branch Exchange), this approach can ensure that access to the servicing port of the installation will be precluded even in case of direct access to the lines of the Telekom. Otherwise, a similar degree of security could only be achieved with the help of cryptological means.

Disadvantage: All maintenance work must be carried out directly on the facility. Failing any additional measures, e.g. removal of the maintenance PC to the adjacent room, the maintenance staff will always have access to the PBX facility as well. The remote interfaces are often not only used for remote maintenance. Remote signalisation needed for the operation of the PBX network is occasionally carried out via the same interfaces. In such cases, dispensing with remote maintenance would mean dispensing with central network management. If a remote interface is only to be used for remote signalisation purposes via modem, this modem should be configured in such a way that calls cannot be received.

Additional controls:

• Which reasons speak for and which reasons speak against the relinquishment of remote maintenance?

• Has a corresponding decision on remote maintenance been made?