Study on the security of the system enablers for devices having Multiple Universal Subscriber Identity Modules (MUSIM)
The present document contains the study of system enablers for devices having multiple Universal Subscriber Identity Modules (USIM) in the EPS and 5G system architecture are studied in 3GPP TR 23.761 [2]. The present document provides the security and privacy issues related to MUSIM architecture and lists potential solutions for identified key issues including.
- Security and privacy issues exposing the Paging Cause in clear text in paging message.
- Security aspects of the communication between UE and Paging Server and exposing Paging server address.
- Security and Privacy implications if a Multi-USIM device needs to explicitly indicate to the MNO owning one USIM and that UE is also registered via another USIM at the same or different PLMNs.
- Security aspects of Paging Response with cause value busy indication.
Finally, the present document provides some conclusions for potential normative work.