Researchers Easily Slipped Weapons Past TSA’s X-Ray Body Scanners | Hacker News Reader

Researchers Easily Slipped Weapons Past TSA’s X-Ray Body Scanners

wired.com

76 pointsejr41 comments

"The only useful airport security measures since 9/11, were locking and reinforcing the cockpit doors, so terrorists can’t break in, positive baggage matching and teaching the passengers to fight back. The rest is security theater.”[0] --Bruce Schneier

[0] http://www.vanityfair.com/culture/features/2011/12/tsa-insan...

Hi! Lead author here.

We'll be giving a talk on this work tomorrow at the USENIX Security conference, but I'd be happy to answer questions here before then!

Good luck catching your flight :-)

What were some of the challenges of carrying out these tests? And I imagine procuring the machine may have been an issue if the manufacturers knew you were exposing their shortfalls.

You'd be surprised how difficult it was to bring it on campus and actually turn it on! Over the course of the project, we worked with our IRB, radiological safety experts, regulatory compliance, and campus public safety before we put someone in front of the device. We set the machine up in a lab with a concrete wall to backstop the radiation, and had a 2 meter safety zone around it while it was actually emitting X-rays.

As for procurement, we purchased our machine on eBay from a private seller who purchased it from a U.S. government surplus auction.

You're saying that compliance with university radiation safety protocols was difficult -- for a machine that has been installed around the county and used to expose millions of passengers? I think that's a big part of the story.

Not unless the weirdnesses of ethics panels is part of the story.

Hi,

Have you tried concealing things under a couple of inches of a biological material and wrapping that to the body (beer gut, pregnant lady)?

Specifically, I'm thinking a a few large chunks of ham, coupled with some transglutaminase to aid in the forming of a "meat shield".

Yes we did! Any organic material shows up pretty well under backscatter X-ray, and so can be used to cover darker contraband. You can see this done with Teflon in our gallery: https://www.radsec.org/gallery.html under "Concealing a Knife by Masking".

We didn't try meat due to the mess, but it would almost certainly work as well!

(Technically, in this X-ray energy spectrum, the amount of backscatter is related to the "effective Z" of the material, where Z is the atomic number of the elements involved. Materials made from lighter elements like carbon and oxygen? Backscatters well. Heavy elements like iron? Absorbs x-rays.)

Yeah, I guess I thought they might have something a bit more spectographically advanced to determine molecular makeup rather than just backscatter (something that might distinguish teflon with it's abundance of fluorine from organic matter). It seems like a much more crude instrument than I thought.

For millimeter wave, I'm pretty sure the teflon wouldn't work though, since the millimeter wave machines are likely tuned for organic makeup rather than just backscatter.

Jon Corbett here. Thanks for conducting this study. For some, watching a video of me beating the scanners isn't enough to prove it, but it becomes harder to ignore when a scientific study confirms it. It's also nice to see confirmation of the "pancake exploit" which those critical of the machines have suspected for years.

It is disappointing just how compliant people are with the stupid procedures.

But then you see the stories about people who are in the right, and are complying with the TSA procedures (going as far as having letters from TSA) who get terrible treatment.

http://rt.com/usa/154672-tsa-breast-milk-settlement/

It sucks, but you really have very few alternatives, only 1 of which will actually get you onto the plane so you can get to where you're going and most of which will ensure you'll never get on a plane again.

The procedures may be stupid, but people do weight the options and can be surprisingly rational given that set of choices.

Given a choice of "get scanned and get on the plane" or "instigate an armed overthrow of the TSA checkpoint" I'm probably going to go with getting on the plane myself.

There is the third option of "comply so that I can get onthe plane, but vigorously campaign (or at least write a single letter to my elected representative) to change the policy".

>It is disappointing just how compliant people are with the stupid procedure

Well sure, but this above statement makes me think you want to see people do a more immediate demonstration against the system.

I opt out of the nude scanners every time I fly. I've never had an exceptionally unpleasant experience with the nut-gropers, but I'm a young, white, male so your experience may vary.

I have a dream of everyone opting out, overloading the system and requiring a fundamental change. But I'm always the only person doing it.

At a previous job I traveled a few times a month. I opt-ed out each time or found a line with only a metal detector. After the new pat-down rules were released, I opt-ed out, got the new pat-down and realized that the pat-down was far more abusive and uncomfortable for me than the scanner. I now use the scanner.

Of course, the new pat-down rules were specifically designed to make the experience bad enough that people wouldn't opt-out anymore.

I used to opt for the grope (also never had a particularly bad experience), but kind of threw in the towel after the airports switched from backscatter to millimeter wave.

I've opted out over 50 times (and I try to help collect data about screening methods on FlyerTalk, though I keep thinking this needs to be organized better -- there are so many people collecting it in separate places, including different FlyerTalk threads and different web sites). I think it's interesting that the attitudes of screeners, as well as the thoroughness of their pat-downs, has varied so much. (Some of them have tried to talk me out of opting out, others have been very matter-of-fact, others have fairly vocally criticized the body scanners or TSA itself.)

Three times there was another person opting out within my sight and at least twice I got to talk to a fellow opt-outer (opter-out?). As I recall, their concerns were always more health-related than privacy-related, unlike mine, so I had a bit less common ground with them than I first expected to.

On two consecutive flights (more than a week apart and from different airports) I alarmed the ETD and got detained and subjected to multiple pat-downs and a hand-search of my luggage. I still haven't figured out what caused it, but I put my shoes and backpack through the laundry and it's never happened again. One hypothesis is that I might have gotten a drop of plant food on my shoe, which has made me much more paranoid about touching fertilizers.

You can always opt out. You'll get a pat-down instead and they'll make you wait 5-10 minutes, but I always do that unless I'm running very late. If enough people do, they usually get fed up and open the metal detectors.

Back when they had the backscatter x-ray machines at Sea-Tac, there always seemed to be one lane where the metal-detector was being used instead.

Don't know if this was a coincidence (I don't fly that often), or if they hoped that trouble-makers would chose that lane, and save them from having to do too many pat-downs...

You can research this a bit on FlyerTalk -- the term favored by body-scanner critics for this situation is "SDOO" (self-directed opt-out, when passengers have a choice of screening methods based on which line or checkpoint they choose). SDOO opportunities appear to be getting rarer in the U.S. over time.

TSA is also giving people an incentive to sign up for TSA Pre because (at airports that support it) the Pre line is always metal-detector-only. Right now they are "testing" Pre and randomly directing large numbers of passengers through the Pre line, but the theory is that it will be available only, or mainly, by subscription in the future, which includes some kind of background check. I'm not very comfortable signing up for one kind of government information collection to avoid a different kind, but people who don't like the scanners and don't have that objection might be interested in signing up for Pre.

The article title is false. Within the article it admits the TSA no longer uses this type of body scanner.

"the X-ray scanners are still installed in courthouses, jails, and other government security checkpoints around the country."

Thus the falseness of the article title. The title suggests that terrorists can take over planes using these methods, which is not the case.

It is validating prior claims from a blogger whom the TSA did everything they could to discredit.

Can you (or anyone) suggest an accurate, neutral title?

The article notes the $1 billion spent to deploy the machines, and later states that these machines are no longer in use. What is left unsaid is the cost to deploy the machines that replaced this model–suggesting another billion spent on more security theatre.

The $1 billion number covers procurement, deployment and usage of both the Rapiscan Secure 1000 backscatter X-ray and L3 ProVision millimeter wave AIT systems.

The Secure 1000s have been removed; the L3 ProVisions are still deployed in airports.

I wonder how much of a dose of radiation they exposed themselves (or their grad students) to while researching this?

Hi! Lead author here.

We only had a person in front of the X-ray scanner a few times, to minimize exposure. Most of the time we scanned a radiological "phantom", which is designed to look exactly like a human under the X-ray spectrum.

Are you going to test the millimeter wave style machines as well?

The linked article says that they haven't been able to acquire one for testing.

That's correct. We think the millimeter wave machines should be looked at in a similar adversarial study, but we don't have access to one for testing.

I wanna know how this kind of experiment actually works.

> Bill: "Hey Joe, we're gonna do an experiment, and we need you to smuggle a chainsaw through airport security."

> Joe: "All right. Hold my sign, I don't wanna lose it."

> TSA: "Is this a chainsaw?"

> Joe: "I'm a researcher, I swear."

> TSA: "Likely story. FULL CAVITY SEARCH, FELLAS."

> Bill: "Hmm, that didn't work. Next up, flamethrowers. Hey Frank..."

They would have used their own machine in a controlled setting to ensure it's the machine they're testing, not the temperament of the TSA agents

  ...the University of Michigan, and Johns Hopkins plans to reveal their own results 
  from months of testing that same model of scanner

That's correct. We have our own machine and tested it in a lab setting; we never attempted to smuggle contraband in the field.

Ah, that makes sense.

The scanners are available outside of airports. The university could easily purchase one for study.

You could read the article, it's all there.

I could, but then my joke wouldn't work.. ah well. :)

Reply on news.ycombinator.com