Karl Norrman | Ericsson Research Blog

Ericsson Research Blog

Research, insights and technology reflections

Karl Norrman

Karl Norrman is a Master Researcher in Security at Ericsson Research, the research branch of Ericsson AB. He works with cryptographic protocols and security architectures since joining Ericsson 2001. He was actively involved in the 4G/LTE security standardization and was Ericsson's security coordinator in 3GPP telecom standardization. He is now working with 5G security research, standardization support and software security. Karl holds an MSc in Computer Science from Department of Mathematics at Stockholm University, Sweden.

Karl Norrman

Detecting false base stations in mobile networks

3GPP standardization takes yet another step to combat false base stations. The security group in 3GPP (called SA3) identified that radio condition information received from devices – which is an integral part of all generations of mobile networks (2G/3G/4G/5G) – could contain fingerprints of false base stations. SA3 has described a solid framework based on this information, enabling mobile networks to reliably detect such false base stations. The framework complements other mechanisms introduced in 5G to protect users against false base stations, for example encrypted long-term identifiers and fresh short-term identifiers. This blog post outlines the framework and describes some practical experiments we have performed in our lab.

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Protecting 5G against IMSI catchers

IMSI catchers are devices used to intercept wireless traffic and trace subscribers by their long-term identifiers (IMSIs). While the phenomenon is often exaggerated, IMSI catchers do pose a threat to subscriber privacy. On-going 5G standardization done in 3GPP is a golden opportunity to improve subscribers’ privacy by constructing a protocol architecture that protects against IMSI catchers.

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