A Formal Analysis of 5G Authentication


Mobile communication networks connect much of the world’s population. The security of every user’s calls, SMSs, and mobile data, depends on the guarantees provided by the Authenticated Key Exchange protocols used. For the next-generation network (5G), the 3GPP group has standardized the 5G AKA protocol for this purpose.

We provide the first comprehensive formal model of a protocol from the AKA family: 5G AKA. We also extract precise requirements from the 3GPP standards defining 5G and we identify missing security goals. Using the security protocol verification tool Tamarin, we conduct a full, systematic, security evaluation of the model with respect to the 5G security goals. Our evaluation automatically identifies the minimal security assumptions required for each security goal and we find that some critical security goals are not met, except under additional assumptions missing from the standard. Finally, we make explicit recommendations with provably secure fixes for the attacks and weaknesses we found.

We have ongoing discussions with the standardization bodies (see CVD-2018-0012 on GSMA Hall of Fame) for improving the standard. The paper attracted some media coverage: Daily Mail, The National, ACM TechNews, The Hill, SRF 4, Tages-Anzeiger (frontpage), ETHZ news (frontpage), The Courier, 20 Minuten.

ACM Conference on Computer and Communications Security