T 5.66 Unauthorised connection of IT systems to a network

In principle, unauthorised connection of an IT system to an existing network (by connecting to the existing cables or using the interfaces in the technical infrastructure rooms or offices) cannot be ruled out. This type of linkage cannot be prevented with available cable designs, which differ solely in terms of the time and effort required to connect to the cable and compromise the data.

The unauthorised integration of a computer into a network is often very difficult to detect, and usually goes unnoticed. This type of access allows monitoring of all data communications taking place in the affected segment and can facilitate the following activities, for example:

• Manipulation of data and software

• Monitoring of lines

• Manipulation of lines

• Replay of messages

• Masquerading

• Analysis of message flow

• Denial of services

• Unauthorised execution of network management functions

• Unauthorised access to active network components