Is it necessary to ensure the security of the E1 digital stream?

Question

Telephony

There is an enterprise, it is planned to introduce a system of corporate IP-telephony, the connection of the enterprise with the PSTN is made through 4 E1 digital streams.
The director of the enterprise wants everything to be as secure as possible, so we want to protect ourselves from everything.
Are there attacks through E1? How to protect yourself from them? Share your experience.

Answer 1

depends on the transmission medium in the operator's area of ​​responsibility.
if TDMoE is incorrectly configured by the operator, it is possible to intercept voice data without special tools.
if "copper" is more difficult, but possible.
optics - very difficult, but just as possible.
Usually there is a whole set of technologies.
about penetration through E1 did not hear.
for implementation there should be a "bookmark" on the side of your hardware.

Answer 2

The most secure is some kind of nonsense :)
As already written above, the main threat is in the provider and the transmission medium.
+
They can break your PBX - from a series of vulnerabilities in dialplans and other things, for example, the lack of verification when dialing an extension number.
+ They
can break the E1 board itself, like intel 82574l ping of death +
They
can break your administrator..
behavior on your equipment and effective implementation of incident/problem management.

Answer 3

Interested in both options. I would like to understand how safe E1 is.