Schneier on Security

Clive Robinson • August 3, 2012 1:40 AM

@ elizilla,

How often does the hotel have to plug something in to that power port? Once every couple of months?

More like once every couple of guests/customers.

Nearly all electronic locks used in hotels have some kind of bypass system be it electronic or mechanical. This is because a Hotel’s idea of security is almost the oposite of what a guest/customers idea of security is.

Your room door is an autherization control designed to produce the minimum of hinderance to those who are autherized and a very moderate level of deterance to those who are not authorized.

To a hotel the “security threat” of thieves is many many times less than that of guests/customers as it is in most hospitality industries. This is because the biggesst threat to a hotel is a lack of revenue.

A guest/customer who is upset by being awoken by another noisy guest/customer or not being able to get into their room is someone who’s business might well go to a rival down the street and discorage others from coming to the hotel with “horror stories” of how they were treated by the hotel and it’s staff.

Thus getting a guest who has spent to long at the bar into their room (because they’ve lost or cannot use their key) before they wake other guests is a very high priority. Like wise those returning to their room to get changed or get a coat or something else from their room so they can go off and enjoy themselves.

So most hotel staff are authorized to open guest looks with the minimum of fuss and delay.

The second biggest threat to a hotels (revenue) security is not having rooms available to accomadate guests/customers so non functioning or broken door locks are not something they want. As we all know from experiance we don’t realy know when a battery is going to run down and the device it powers become non functional. It’s just the same for the electronic door lock so a “power up” port is provided as standard and this is generaly by using a small discrete connector that is put on the underside of the external lock facia. Usually this connector is somethin like an RJ45 connector which is also a good place to alow fast override to give hotel staff fast access to “assist guests” to keep the “guest experiance” as positive as possible.

Now you have to realise that the door lock does not know and does not need to know what the room number is nore do nearly all the autherised persons. What they need to know is that when the put in a key or plug in any other autherisation device the door will open with the absolute minimum of fuss and preferably zero damage.

When you start looking at “electronic door lock security” in what are virtually zero “traditional security” environments and understand what their actuall purpose is not “security” but to minimize nuisance, you will realise that it’s not the physical or electrical design of this lock the manufacturer got wrong. It was the authorization protocol between the lock and the autherization device.

I’ve seen this particular SNAFU over and over again and I fully expect to see it continue for the foreseeable future because there are currently no ince55555555555555555555555555555555555555555

Clive Robinson • August 3, 2012 9:29 AM

@ Firefox,

“threat to hotel’s revenue” stuff implying that profit trumps security (maybe he didn’t mean that exactly).

What I ment is that “they know upsetting their customers/guests” is a revenue losser, and they also know that they have different security metrics.

But the security of their revenue (not their profit if any) is what keeps the hotel in business as amongst other things an employer of people in the local(ish) community and thus in theory as a social good.

That is you could take the view “profit is for shearholders and revenue is for the social good” of employees, suppliers, and associated businesses and is part of “economic churn which is good for the rest of us all be it indirectly through taxation.

The hotel also know that the security of their guests is not just from those unauthorised persons off the street who could in theory do the guests some harm, but also from the guests themselves be it directly (smoking in bed) or indirectly from ill health both of which require quick and easy access for autherized hotel staff and first responders and occur way way more frequently than theft/attacks from unauthorised persons.

If you have ever had to sit through a meeting with large hotel managment on what they want from security products you might at first hearing think they are mad bad and callous, the reality is they are using a risk based methodology and the sort of “security” things you might expect a home owner to list mostly don’t make it onto their lists.

For example on a home for home basis how many people have actually been attacked in their home compared to the number of homes that have had fires? Then consider how few home owners fit even smoke detectors as opposed to window locks etc?

As I indicated there is security and then there is security you have to know which security is more important and why…

And yes as some long time readers know I used to design electronic locks for the various parts of the hospitality industry and other organisations with significantly different security requirments.

@ AC2, Dirk, martino,

Yes it was a keyboard hang up yet again.

As for lying in bed I must put my hand up to that on this occassion, I’m back in hospital trying to charm the nurses and others who have my wealfare in their hands including the porters. A short while after the keyboard locked up a very nice young Italian lady (named Anna) came to take me down for a bit of surgery, so I put off correcting the post. Unfortunatly they have decided not to chop bits off today at the last minute due to unfavourable blood work, so I missed lunch 🙁 and I’m here for the weekend and they will re-run Monday morning.

@ Wael,

Yes there were Tandy stores back then, but there was also Radio Spares (RS these days) but you did not need to make anything fancy to open most battery powered electronic locks, a large magnet would do it probably better.

One of the real issues with battery powered locks is taking a CMOS logic output measured in nano/micro watts and converting it to the sizable fraction of a horse power required to pull back the door strike/latch. In most cases they elect not to do this but put in a keyed drive chain between the handle and latch mechanism and activate the keyway with a very very lowpowered transducer such as a small electromagnet. If you know where in the lock facia it is and it’s orientation it’s fairly easy to place a large magnet such that the transducer gets activated.

This opens not just the door but a large security hole as well… Most locks have a “log” which shows when a door was opened and by whom. But the relity is somewhat different the little micro controler is compleatly oblivious to the door being opened it has no way to tell. All it shows is who was authenticated or when somebody tried to authenticate. Thus a smart thief goes unrecorded if they use a magnet.

Now let us assume you are an insider to the hotel and you want somebody else to “take the wrap” you simply wait for them to come out of the room go out of sight then slip into the room steal something and leave quickly but cautiously and go use your card on another floor way out of the way as an alibi… After a few episodes of doing this you have the person kind of falsely accused by the lock logs without any way to defend themselves whilst you have an alibi provided by the logs…