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No - I totally get the point. But, if you are going to engage in criminal activity, the bar to your destructive behavior isn't a $650 transmitter. It's a $20 containers of gasoline.

If you want to hurt people, it's pretty much impossible to stop you from doing so (or even slowing you down) - all we can do is catch you, and put you in prison after you do so so that you can't hurt more people.

I'm not suggesting we ignore security (I like SSL, and passwords on my accounts) - but we can't create a world where everyone has to treat the populace as though they are intent on creating destruction. This is the mindset of the TSA and "Search everyone, because any one of them might be carrying a bomb." At a certain point, we have to trust that the vast, vast majority of people are good.

And, in the whole scope of things, jamming an LTE radio transmission system has pretty big penalties, and very little financial payoff, and a pretty good chance of being caught. It's one of those asymmetric criminal activities that is balanced in favor of society, and against the criminal.

Where you want to put your attention in enhancing defenses, is places where there is a strong incentive to commit the crime, and less chance of being caught. Guarding against petty thieves, lots of safeguards/fraud alerts around things like credit cards, or your paypal account. That's where attention needs to be spent.

You know where it's important to spend a lot of money on counter-jamming? Life Safety systems like Nuclear Power Plants, or Plane/Car navigation systems. Where lives are on the line, I totally agree that we need to harden, harden, harden those systems. Also, SCADA systems - that control large amounts of underlying infrastructure. And the Stock Exchange. Spend a fortune on ensuring that the bad guys can't cause havoc, kill people, or create large economic damage.

Perhaps your LTE/Cellular coverage is better than mine, but I'm pretty used to having to track down a WiFi connection to get any serious work done, or make a reliable Skype call. I don't put LTE coverage in the "Mission Critical" category of infrastructure.

Also, if you are in a situation (Prison, battlefield) where the vast majority of your opponents are intent on doing you harm, you also harden the crap out of everything. And pay the price - because you need to.

But, all else equal, I'd rather have the money/resources that might have gone into putting MILSPEC anti-jamming capabilities into my LTE NIC, instead be spent on making it cost less, draw less battery, and give me more bandwidth.

Let the FCC catch the 3-5 jammers at year intent on doing harm, and put them in prison to consider the wisdom of their behavior.




I think you're arguing at cross-purposes. You are quite right in relation to crime or vandalism by a member of US society carried out for mere profit or malice. But consider the more troubling case of terrorism or similar organized attack. If one can disrupt cellular communications on a large scale parallel to an attack on physical infrastructure (eg a bomb or...), the immediate and economic damage could be significantly multiplied. Likewise, consider temporary but coordinated outages in 10 or 20 major metros. It would be difficult to catch the perpetrators but would impose considerable economic costs.


I think the key is to understand what should be considered part of our "critical infrastructure" and ensure that is reliable.

For example, when I was managing the IT organization for our company, despite the fact that everyone in the office has a cell phone, and despite the fact that they also have a VOIP phone (Polycom Soundpoint IP 501 SIP), that is driven of of POE connections, and we have a generator with 36 hours of diesel supplying the routers/switches that supply those phone - Every conference room had a POTS (Plain Old Telephone Systems) analog phone line that was cross-connected with a piece of copper at our punch-down block, directly to the 300 pair coming into our MPOE - no active electronics (on site) required. Those land lines are the critical infrastructure, that need to be defended (along with COs backing them up).

If someone comes up with a good (cheap) attack against them, that will get my attention.

I guess another way of approaching this is, if Police/Fire/Medical organization start relying on LTE systems, and those LTE systems become a critical part of our infrastructure for economic/infrastructure/life safety systems, then yes, we need to start focussing on hardening them.

This is my way of saying yes, when we wargame this out, we should consider "What happens if there is an extended LTE outage during a disaster, does this impact our first responders significantly? And if so, we need to take steps to protect ourselves there."

Important to note - it's highly unlikely that any group of people will be able to establish a coordinated attack on 20 major metros. That level of conspiracy would be stopped by the time planning got to the 3-5 city attack.

And that's another point - let's not spend large sums of money trying to harden the LTE system (though, reasonable investment makes sense, so the research presented is good) - but instead, let's direct those resources to tracking (and stopping) the bad guys that would do this sort of thing in the first place. That, then, protects us from all of their attacks, not just the LTE wireless system.


I agree that the primary focus should be on critical infrastructure. But an important part of asymmetrical warfare is also to cause destabilization through uncertainty. If 4g is the norm 2 years from now and older technologies are being phased out, then disrupting the cellphone network in DC during the morning rush hour, for example, is likely to set off sufficient alarms and panic reactions that the response outweighs the disrupting incident itself. When I was younger I lived in London and the IRA was still conducting a terrorist campaign of bombing civilians as well as government targets in that city. They didn't set off bombs that frequently, but they issued bomb threats against the subway network on a near-weekly basis, and of course the authorities couldn't just blow off a bomb threat, so people's day-to-day travel routines would be disrupted at least once a month as one or other subway line were threatened.Nobody dies, but over time it adds up to a significant economic drain, to say nothing of the psychological burden it inflicts on the populace.

Important to note - it's highly unlikely that any group of people will be able to establish a coordinated attack on 20 major metros. That level of conspiracy would be stopped by the time planning got to the 3-5 city attack.

The beauty of such an attack (from an asymmetrical PoV - obviously I don't endorse such things) is that the you don't have to deal with proscribed or highly controlled things like explosives. This means that the stakes are low and you can afford redundancy. If you disrupt the LTE system for an hour at a time on a random weekday using a mobile transmission source, you could probably get away with doing so for a while. Again, the public perception that even consumer information (rather than critical) infrastructure can be disrupted at some malicious actor's pleasure is an implicit win for a hostile organization or state actor.


I'm not even sure that is possible to harden a wireless system to the point where an attacker can't bring it down for many orders of magnitude less investment than what it cost to put it up in the first place. The more sophisticated the more likely it can be brought down. If you want to get through use CW (Morse) and plenty of juice.


Actually such systems can be built, I saw a demo of one based on UWB tranceivers, it was proposed replacement for the JSTARS system. The reason it worked was that 'dumb' jammers needed to raise the entire noise floor, and 'smart' radios were using singletons (single pulses of RF energy across a wide spectrum of possible frequencies) so a small transmitter could use kilowatt nanosecond pulses which always landed above the noise floor.


That's amazingly clever.

If I get you right this beat on the 'dumb' jammer because the power imbalance worked to the advantage of the defender: knowing when to listen for the very short pulse at high power level coming from the transmitter and ignoring its input the rest of the time other than to establish a baseline noise level, whereas the jammer would have to blanket the whole spectrum not knowing when the next pulse would be until it came?

So essentially the only way to break the system would then be to figure out ahead of time when a pulse would be transmitted and presumably the sequence of intervals between pulses was sufficiently hard to predict that this would take much longer than it took to get to the point of the next transmitted burst?


That was pretty much the way I understood it to work, I didn't get to see 'behind the curtain' sadly. Two bits of the 'secret sauce' were keying sequencing / syncing and basically a frequency agile transceiver that operated at really high frequencies across a very wide chunk of spectrum.

The claim was that the only "known" way to jam the system was to raise the noise floor to the point where the pulses could not be distinguished, and they showed a number of scenarios that didn't work.


> Important to note - it's highly unlikely that any group of people will be able to establish a coordinated attack on 20 major metros. That level of conspiracy would be stopped by the time planning got to the 3-5 city attack.

It's trivial to do. Make a bunch of jammers on timers, and plant them around dozens of major cities at your leisure. One disaffected person working alone could do it.

P.S. Magnetrons are tunable by simply changing the magnets, and microwave ovens can be had for $20 apiece if you buy in large quantity. It does not cost $650 to make a very powerful jammer.


The more high-tech a society is the more vulnerable it is to this kind of attack. Infrastructure that isn't there can't be broken.


> I don't put LTE coverage in the "Mission Critical" category of infrastructure.

The problem here is that officials are considering using LTE for communication between emergency responders. And that would make LTE very much "mission critical".




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