T 5.66 Unauthorised connection of IT systems to a network

In principle, the 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 prevented. There is no cabling design that could prevent this type of connection. Cabling designs differ solely with regard to the time and effort required to connect to the cables and to read or upload data.

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

• manipulation of data and software
• line tapping
• manipulation of lines
• reimporting messages
• masquerading as other communication users
• analysis of the message flow
• denial of services
• unauthorised execution of network management functions
• unauthorised access to active network components