02.093GPPRelease 1999Security aspectsTS
The use of radiocommunications for transmission to the mobile subscribers makes PLMNs particularly sensitive to:
‑ misuse of their resources by unauthorized persons using manipulated Mobile Stations, who try to impersonate authorized subscribers; and
‑ eavesdropping of the various information which are exchanged on the radio path.
It can be seen that PLMNs intrinsically do not provide the same level of protection to their operators and subscribers as the traditional telecommunication networks provide. This fact leads to the need to implement security features in a GSM PLMN in order to protect:
i) the access to the mobile services;
ii) any relevant item from being disclosed at the radio path, mainly in order to ensure the privacy of user‑related information.
Two levels of protection are therefore assumed:
‑ where security features are provided, as defined in clause 3, the level of protection at the radio path of the corresponding items is as good as the level of protection provided in the fixed networks;
‑ where no special provision is made, the level of protection at the radio path is null. All items which are not dealt with in clause 3 are therefore considered to need no protection.