vSIM (Virtual SIM)

A virtual SIM is a software implementation of SIM functionality that runs without dedicated tamper-resistant hardware, typically on a smartphone or IoT module. Vendors use vSIMs to enable instant onboarding, multi-IMSI roaming, and devices without a SIM slot. Because the secret key is held in software or in a less hardened secure element than a UICC or iSIM, vSIM security depends heavily on platform protections; GSMA-compliant eSIM/iSIM remain the preferred path for high-assurance deployments.

Categories: Radio Access NetworkRoaming and InterconnectIdentity and Subscriber

vSIM in context

The radio access network is where mobile devices attach to the operator's infrastructure. Attacks in this layer include IMSI catching, rogue base stations and downgrade attacks; defenses rest on mutual authentication, integrity-protected signaling and Open RAN supply-chain hygiene.

Roaming and interconnect are where two operators exchange signaling and user-plane traffic. Trust boundaries here are the primary attack surface for location tracking, SMS interception and fraud, which is why GSMA now mandates SEPP with PRINS on 5G interconnect.

To place vSIM in the wider telecom-security picture, review AKA, iSIM, MNC, SUPI, SUPI Concealment and PLMN ID — each entry cross-references back to this page so you can walk the topic in either direction.

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