SIM card makers hacked by NSA and GCHQ leaving cell networks wide open

Using a fake cell tower and holding SIM encryption keys, spies are able to listen into conversations over mobile networks without asking the courts for permission for a wiretap. The method is also difficult to trace, so risk of discovery is low.

To steal the SIM encryption keys, MHET exploited a weakness in SIM manufacturers' business routine—that SIM card manufacturers tend to deliver the corresponding Kis to mobile carriers via e-mail or File Transfer Protocol. By doing basic cyberstalking of Gemalto employees, the NSA and GCHQ were able to pilfer “millions” of SIM Kis, which have a slow turnover rate (your phone's Ki will likely remain the same as long as you keep the SIM in the phone) and can be used to decrypt data that has been stored for months or even years.


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[link to arstechnica.com]