RE: RFID Tags

["lsi" <stuart () cyberdelix net>]

[collated replies to a number of repondents below]

> It seems to me that some of these attacks sound great at first, but break
> down when you consider how it would REALLY play out.  For one, if you get on
> the train and inventory everyone's clothing...how do you know which shirt
> goes with which pants or shoes? 

Easy - signal strength.

> As for credit cards, this is extremely easy to deal with.  The cards
> themselves that have been seen so far have a very limited range, measured in
> inches.  I can think of a wallet design that would shield the cards a bit,

It's a plan, but this is just asking for the Black Hat to use a 
stronger transceiver.  It's just building a higher fence; not really 
a long-term solution.

> up against everyone like a comically-indiscreet pickpocket.  And this all
> assumes that all the credit cards in the wallet don't respond at the same
> time, on the same frequency, thus garbling the results.

This problem will have been overcome in the design of the RFID, as 
they are specifically intended for use in counting large batches of 
goods.

> I don't think RFID was ever intended to be a feature of security, but rather
> one of convenience. 

Unfortunately, the real world dictates that security be a feature of 
pretty well everything.

> Tags have to recive the right signal to transmit the data back. If tags
> could be queried by any device wireless networks (900Mhz) would be flooded
> with 900Mhz tags. Wal-Mart is going with the 915Mhz tags so that problem is
> unacceptable. You have to know what to send a tag to get it to respond.

OK, but say the chips are put into cash.  Every till on the planet is 
gonna know what frequency to use.  So, the Black Hat can make a 
transceiver for that frequency.  Passport RFIDs will also have a 
standard frequency - so he can make his transceiver support that 
frequency too.  In fact, due to the homogenised nature of modern 
commerce, there may well only be, in the end, a small number of 
frequencies that are used.  So Black Hat will end up with the RFID 
equivalent of an autorooter.  It knows which frequencies are for 
what, and it tries them all.

> You run the same risks with using a computer or storing data on any device,
> including pen and paper. A tag id by itself is worthless unless you know
> exactly what data is stored on it.

I imagine that a database will be built which will list individual 
numbers, and ranges of numbers, which are known to correspond to 
specific items.  

But wait - you're saying the tag ID is not the only data on the tag?

> A RFid tag has big limitations too, once you chop off part of the antenna
> it's worthless. The physics of radio waves limits that.
>
> You can't be tracked "everywhere" you go. It's not cost affective at all. A
> tag will transmit around 9 feet.

My understanding is that if you pump more voltage into your 
transmission, the tag will transmit further.  

This is because the tag simply receives the signal and, using the 
power in the signal it received, transmits its ID.  If you exceed the 
rated spec by, say, 15%, the tag might transmit 15% further than its 
rated range.  You might be able to snoop when you should not be able 
to.  ...Or maybe not - that's what the pen-test is for.  

> Tags can be shut down (killed) in a second with a reader.

Sweet.

> Instead of fearing new technology, how about working with it to find the
> best ways to use it?

Well, because someone else will be working to find the best way to 
*abuse* it, of course.  It makes sense to anticipate this activity, 
so as not to be burned by it.  Again, this is what the pen-test is 
for.  

If it was my system vulnerable to attack, I would be scared, yes.

I don't make a habit of "working with" defective products - I try and 
replace them!

> Tech. improves every day, either we can work with it, or fight it and go
> back to the stone age. I would rather work with it so I can have the
> challenge of security then not have advancements at all.

Advancement for advancement's sake alone is Bad.

When the "challenge of security" can cost people money, waste their 
time, violate their privacy, or otherwise, cause them misery, the 
technology should not be used.  It's a liability, as the lawsuits 
that will follow will surely prove.

Deploying a half-baked solution is just not a good idea.

Stuart

---
Stuart Udall
stuart at () cyberdelix dot net - http://www.cyberdelix.net/

--- 
 * Origin: lsi: revolution through evolution (192.168.0.2)


------------------------------------------------------------------------------
Ethical Hacking at the InfoSec Institute. Mention this ad and get $545 off
any course! All of our class sizes are guaranteed to be 10 students or less
to facilitate one-on-one interaction with one of our expert instructors.
Attend a course taught by an expert instructor with years of in-the-field
pen testing experience in our state of the art hacking lab. Master the skills
of an Ethical Hacker to better assess the security of your organization.
Visit us at:
http://www.infosecinstitute.com/courses/ethical_hacking_training.html
-------------------------------------------------------------------------------