While carriers are involved in rolling out promises about new and whizzier 5G wireless networks at the recent telecom shows of the past weeks -- we're looking at your Mobile World Congress -- researchers at Purdue University and the University of Iowa have taken at look at the networks that we still routinely use -- and they aren't happy.
In a paper entitled LTEInspector: A Systematic Approach for Adversarial Testing of 4G LTE, researchers at the two schools uncovered some new vulnerabilities that affect all the 4G Long Term Evolution (LTE) networks that are now in use.
Researchers found that the attach, detach and paging procedures of these networks will allow connection without valid credentials being present.
An attacker could exploit this particular vulnerability to steal someone else's identity, send messages that would seemingly coming from someone else, and intercept messages meant for a user.
Additionally, attackers could spoof the location of a mobile device, or cause other devices to disconnect.
Another kind of possible attack could even inject false warning messages such as malicious Amber alerts or fictitious emergency warnings.
It appears that the basis of these attacks is a lack of proper authentication, encryption and replay protection in the protocol messages that are in use.
The researchers developed a testing framework they called LTEInspector that helped them find ten new vulnerabilities in 4G LTE and verify the nine that had been previously known.
They also built a test network with off-the-shelf hardware and an open source LTE software stack to test the findings, and directly verified eight of them. While this was good for the researcher's work, it shows that the same setup could be constructed and used for an attack by a determined adversary without undue cost.
LTEInspector has been open sourced on GitHub.
The researchers' finding may not cause any change to happen in 4G LTE. Previous flaws in the network that have been discovered are still present and widespread.
It seems that carriers have a high inertia factor regarding any protocol changes needed on the networks. The carriers worry about backwards compatibility impacting their operations.
But some solutions -- the authentication relay attack described in the paper, for example -- do not require that major infrastructural or protocol overhauls be done. The authors even suggest in the discussion section that a distance-bounding protocol would work as a defense. Whether this will come to fruition remains to be seen.
Still, until the flaws in 4G LTE that they have shown are rectified one way or another, the authors have decided not to publish their PoC attacks. This seems merciful to the rest of us, especially as we wait for the 5G's arrival.
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— Larry Loeb has written for many of the last century's major "dead tree" computer magazines, having been, among other things, a consulting editor for BYTE magazine and senior editor for the launch of WebWeek.