English term (edited): (risk of ...) diversion of data

What they are talking about is that technically at any nod in a network - including the Internet - it is possible to make an identical copy of the data stream and send it some unintended other destination.

Network tap

A Network TAP (Terminal Access Point) denotes a system that monitors events on a local network and in order to aid administrators (or attackers) in analyzing the network.[1] The tap itself is typically a dedicated hardware device, which provides a way to access the data flowing across a computer network. In many cases, it is desirable for a third party to monitor the traffic between two points in the network. If the network between points A and B consists of a physical cable, a "network tap" may be the best way to accomplish this monitoring. The network tap has (at least) three ports: an A port, a B port, and a monitor port. A tap inserted between A and B passes all traffic (send and receive data streams) through unimpeded in real time, but also copies that same data to its monitor port, enabling a third party to listen. Network taps are commonly used for network intrusion detection systems, VoIP recording, network probes, RMON probes, packet sniffers, and other monitoring and collection devices and software that require access to a network segment. Taps are used in security applications because they are non-obtrusive, are not detectable on the network (having no physical or logical address), can deal with full-duplex and non-shared networks, and will usually pass through or bypass traffic even if the tap stops working or loses power.
...
https://en.wikipedia.org/wiki/Network_tap

so strictly speaking what gets "diverted" to some third party is a copy of data sent or received, the original data do get to the intended destination.

You could also call it less euphemistically "електронско прислушкивање" by analogy to "прислушкивање телефонских разговора".

The concept of DigiTask intends to install a so called Skype-Capture-Unit on the PC of the surveilled person. This Capture-Unit allows recording of the Skype communication, such as Voice and Chat, as well as diverting the data to an anonymous Recording-Proxy. The Recording-Proxy (not part of this offer) forwards the data to the final Recording-Server. The data can then be accessed via mobile Evaluation Stations.

Functions of the Skype-Capture-Unit

Live diversion of voice
Live diversion of chat
Live diversion of video
Live diversion of data
Skypein
Skypecasts
SkypeSMS
Buddylist
compressed data transmission
encrypted data transmission
streaming-capable mediaplayer
Obfuscation of Recording-Server address via proxies
Time-restricted usage (will self-delete after a set time-frame)

https://wikileaks.org/wiki/Bavarian_trojan_for_non-germans

more:

https://www.google.co.uk/search?q="diversion of data"