A.3 Compromise of authentication data

21.1333G security3GPPSecurity threats and requirementsTS

Authentication data can get compromised, either during its transport between the home environment and the serving network, or by unauthorised access to databases.

– Forcing use of a compromised cipher key

The intruder obtains a sample of authentication data and uses it to convince the user that he is connected to a proper serving network, and forces the use of a compromised cipher key. The intruder may force the repeated use of the same authentication data to ensure the same encryption key will be used for many calls. Leads to continuous eavesdropping.

– Impersonating the user

The intruder obtains a sample of authentication data and uses it to impersonate a user towards the serving network. Masquerading as a base station towards the serving network (or eavesdropping on such a connection) could be used to obtain valid authentication data for this attack.

– Reusing authentication data

The intruder forces the repeated use of the same authentication data. Weaknesses in the efficiency of the encryption protection may be exploited either for cipher cryptanalysis or protocol attacks.