These aren't just theoretical attacks, either. The team tested eight of the ten attacks using SIM cards from four large US carriers.

While the issues have to do with LTE itself, it is possible to fix them -- at least one of the big US carriers already has. There's still a race against time, however. You can build the necessary LTE exploit tool for as little as $1,300 using readily available parts, so a determined attacker could infiltrate a network without an abundance of resources.

This stresses the importance of testing cell standards in the real world. It's relatively easy to fix security flaws before a standard is finalized and rolls out in earnest -- it's another when it's already in use by cell carriers that may have to patch vast networks.