Malicious SIMs can hijack smartphones, steal files, and lock them onto 2G

Aug 11, 2026 - 15:00
Malicious SIMs can hijack smartphones, steal files, and lock them onto 2G

Researchers have found that compromised or malicious SIM cards can issue commands to some smartphones and cellular-connected devices, allowing attackers to steal information, disrupt communications, downgrade connections to 2G, and in some cases execute code. Tomasz Piotr Lisowski and Dr Marius Muench of the University of Birmingham, working with Kristian Covic from Fuzzware, traced this to a legitimate function already built into the cellular spec. That function is Proactive SIM. It lets a card send … More

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