Ask Slashdot: Is TSA's PreCheck System Easy To Game?

OverTheGeicoE writes "TSA has had a preferred traveler program, PreCheck, for a while now. Frequent fliers and other individuals with prior approval from DHS can avoid some minor annoyances of airport security, like removing shoes and light jackets, but not all of the time. TSA likes to be random and unpredictable, so PreCheck participants don't always get the full benefits of PreCheck. Apparently the decision about PreCheck is made when the boarding pass is printed, and a traveler's PreCheck authorization is encoded, unencrypted, on the boarding pass barcode. In theory, one could use a barcode-reading Web site (like this one, perhaps) to translate a barcode into text to determine your screening level before a flight. One might even be able to modify the boarding pass using PhotoShop or the GIMP to, for example, get the screening level of your choice. I haven't been able to verify this information, but I bet Slashdot can. Is TSA's PreCheck system really that easy to game? If you have an old boarding pass lying around, can you read the barcode and verify that the information in TFA is correct?"

Comments

Yes

[Jeremiah Cornelius]

Yes it is.

Re:Yes

[Spiridios]

Way to get every /. member on the no fly list.

Re:Yes

[Mitreya]

Yes it is.

Wrong question is being asked

A better question is -- Would it matter if TSA PreCheck System were easy to game?

Seeing how TSA has no record of ever catching or thwarting a terrorist, I would say "no"

Re:Yes

[Anonymous Coward]

Wrong question is being asked

A better question is -- Would it matter if TSA PreCheck System were easy to game?

Seeing how TSA has no record of ever catching or thwarting a terrorist, I would say "no"

No, neither question is really relevant. It doesn't matter if the system is easy to game for someone with technical aptitude because this whole system isn't really about making travel more secure, but conditioning people to be more complacent about government intrusion and restriction on their daily lives.

Re:Yes

[gmanterry]

Way to get every /. member on the no fly list.

It's probably dangerous to even comment on this article. It's probably a Homeland SecurityTSA sting.

Re:Yes

[Joe Decker]

Well, they're semi-effective at catching TSA employees who steal iPads, laptops and expensive camera gear.

No, they're not. There are occasional busts, but most go unreported or unaddressed.

Fun fact: The TSA refuses to report such thefts to local authorities, as a matter of policy.

Re:Yes

[Jeremiah Cornelius]

" this whole system isn't really about making travel more secure, but conditioning people to be more complacent about government intrusion and restriction on their daily lives."

DING DING DING DING DING!

Ladies and gentlemen, please lower your bids. We have a winner.

Re:Yes

[Anonymous Coward]

this whole system isn't really about making travel more secure, but conditioning people to be more complacent about government intrusion and restriction on their daily lives.

Parallel to that, army and police have been having Zombie Apocalypse training lately. Training them to fight crowds of unarmed human-shaped figures. Considering the lack of real zombies, I wonder what that's supposed to condition the army and police for...

Re:Yes

[Jeremiah Cornelius]

Did you notice, how I was able to get in "at the front of the line" on this discussion thread?

Re:Yes

[Anonymous Coward]

I am not a fan of the TSA, but let's be fair here: the purpose of doing security checks is not to catch terrorists with bombs in their shoes, but rather to eliminate shoe-bombing as a viable form of attack.

The problem is, there are a large (but not technically infinite) number of such attacks. With the TSA only re-acting to the threat as it is used, that means there are (largeNum -1) attacks remaining. So, with such a large number of attacks to choose from, any terrorist would have no problem with the TSA.

In other words, the TSA only started checking shoes after someone tried to hide a bomb in one. The TSA only started their asinine 3-1-1 liquid rules after a liquid bomb plot was uncovered. And no doubt, the TSA will start rectal exams after a terrorist shoves a bomb up their ass.

Responding to the PREVIOUS threat is not security.

Re:Yes

[Teancum]

What would be your response if a liquid bomb threat was discovered and then the TSA did nothing to screen for it? Everyone would be screaming their heads off that the TSA should be checking for known threats. It is absurd to try to claim that the TSA airport checks are not security.

Not everybody is screaming for increased authority being given to the TSA to declare martial law in airports. Too far? I think it was too far on September 10th, 2001, as the security procedures in pace prior to the 9/11 attacks should have stopped those terrorists from getting on board those planes in the first place as well as stopping even the shoe bomber.

These guys are simply being lousy rent-a-cops that really don't know the first thing about how to act as a law enforcement agency in a once free representative democracy. It is sad that they can't simply act like almost every other police agency acting outside of those airports and *gasp* actually investigate crimes when they happen, to do gum shoe detective work, and root out would be criminals who might be causing problems. I also think this "zero tolerance" for terrorist actions is maddening as well.

The real issue here is that stupid people do stupid things. We can't afford to have TSA level security in malls, public schools, banks, or elsewhere. Certainly not in bus stations or on freeways. In reality we can't afford to have this in airports either, but some stupid congressmen had a knee jerk reaction to a non-problem and didn't really address the issues involved either... trading one form of corruption for another.

What the TSA should be doing is real security and police work in airports. There may even be a need to keep it a federal agency, so far as threats to airport security typically do cross state borders and even become international problems. There are even national security issues involved so far as there are foreign governments who are using "terrorist groups" as surrogates to cause chaos and disorder deliberately in an attempt to further their own national goals. Yes, I'm saying that Al-Queida and other similar groups are not merely spontaneous but rather are supported, financed by, and encouraged by many countries (almost all of whom have seats at the United Nations along with national capitals and recognizable leaders) and this is a real war going on.

If these doughnut loving idiots would get off their behinds, turn off their scanning machines, and actually do some real police work to find those people who are causing problems... then I might be encouraged by the work that the TSA is doing. For now, I consider them to be lazy asses that are wasting billions of tax dollars on a futile exercise that won't stop a real terrorist attack in America by somebody determined to cause problems. This security theater is utter bullshit and needs to stop. If there is a real threat that soliders or mercenaries from foreign governments are coming into America... they should also be stopped. But it should be painfully obvious who they are as well and stopping those foreign soldiers from committing acts of war inside of America can be done without infringing on the rights of ordinary citizens or molesting toddlers.

Re:Yes

[ericloewe]

The TSA is still doing it completely wrong. You don't try to find weapons or dangerous items, you try to find dangerous people.

Re:Yes

[houghi]

Well, they can't, because what the TSA is actually doing is keeping the terrorists from the planes by employing them. Oh, you were taking about thieves? Well, potato, tomato. Thieves, terrorists, republicans, democrats. Who knows the difference anymore.

Re:Yes

[Sqr(twg)]

Unless you want to give all your flight details to some random web server operator, you're better off installing something like http://sourceforge.net/projects/zbar/ and decoding yourself.

Re:Yes

[xenobyte]

What would be your response if a liquid bomb threat was discovered and then the TSA did nothing to screen for it? Everyone would be screaming their heads off that the TSA should be checking for known threats. It is absurd to try to claim that the TSA airport checks are not security.

The checks are security... security theater that is. They don't work. They don't catch terrorists. They don't prevent terrorists from trying something else.

You mention the liquid bomb incident. First of all, the liquids were not even meant to be taken aboard an airplane. They could have been though and that started the scare. Now, the sensible rules would be such, that it would be impossible to bring enough liquid aboard to create a bomb that could do any worthwhile damage. But no. The rules allow for one liter of liquid to be brought aboard and any half-decent explosives expert could tell you that it takes less than 200 ml of some liquid explosives to create a bomb that could bring down the aircraft. So we've ended up with a worthless rule that doesn't work, but which cause lots of inconvenience and hassle for the traveler. That's security theater - if it's REALLY annoying it must be REALLY effective...

Sure, you can't bring enough liquid explosive to blow a hole in the universe but you can still drop the plane on a major city, and that's usually enough for most terrorists.

Re:Yes

[Teancum]

I'm not a fan of TSA either, but this seems like an unfair standard. How many criminals has the lock on your home door stopped?

The role of a lock on a front door or for that matter an automobile is to keep "the honest people honest". In other words, it is there to stop a 70 year old partially senile old woman from driving off with your car or walking into your house at odd hours because they got lost or confused. It reminds an otherwise honest person that they have gone too far and should likely turn back.

A uniformed officer walking around an airport with a radio and a gun works just fine to do that kind of security to protect passengers, staff, and crew from ordinary civil disorder, where they may have to call in some backup if some guys are getting a bit too rowdy at a restaurant bar or some group of people being too pushy trying to board an airplane. "Ordinary" crimes like assault, murder, and perhaps pickpockets and purse snatchers are legitimate things for a security force to try and keep under control.

Trying to keep some group of idiots who are determined to go postal and start killing random people in some manner is much harder to stop... assuming they can even be identified. Soldiers or mercenaries (however you define those terms) who are acting in the interest of a foreign government and trying to disguise as civilians in an attempt to perform acts of war (this is my own definition of terrorism) seems to be a larger problem... but there are ways to deal with such nations as well. Curtailing civil liberties and molesting grandmothers or toddlers is not a way to get that to happen.

Re:Yes

[Cid Highwind]

DING!

Some people see a monster and need to believe that someone (even someone hostile to them) is holding its leash.

The truth is somewhat scarier: that the continual growth of oppressive-yet-useless security apparatus like the TSA is an emergent property of power, fear, and greed.

Could be a honeypot

[mepperpint]

If I were designing a security system for TSA, I would definitely consider printing a (possibly fake) screening status in the barcode in plain text. If you keep a database of what status you assigned to which boarding ticket, then you can more thoroughly screen (or arrest and jail indefinitely) anyone who changes the easily hackable obvious screening status on their boarding pass. This is much like a honeypot that folks sometimes use in network security. (For those who don't know, a honeypot is an easily hackable machine that serves no purpose except to be hacked so that an observer can find folks who are trying to break in.)

Re:Could be a honeypot

[iiii]

Yeah, and the "who".

Their thought: "hey, well catch the bad guys who are trying to get around security!"
Reality: they catch the nerds who know how to hack barcodes and want to save 10 minutes of waiting in a security line.

But this is giving them too much credit. They are not thinking that far ahead. They are still stuck on shoe bombs (22 Dec 2001).

Re:Could be a honeypot

[Mitreya]

If I were designing a security system for TSA, I would definitely consider printing a (possibly fake) screening status in the barcode in plain text. If you keep a database of what status you assigned to which boarding ticket, then you can more thoroughly screen (or arrest and jail indefinitely) anyone who changes the easily hackable obvious screening status on their boarding pass.

This is an interesting point, but what does any of this have to do with catching terrorists? Now TSA will detain people who mess with barcodes and claim them to be terrorists?

To extend your line of thought -- If _I_ were designing a security system for TSA (an organization that has never caught a terrorist on its own accord), I too would make up an easily game-able system so that TSA can actually arrest some people and then trump such arrests as success and therefore request more funding.

It would be a lot cheaper and just as efficient to go back to pre-9-11 security and invest in an "anti-terrorism rock" for contractors (if contractors must be funded by this).

Re:Could be a honeypot

[girlintraining]

It's not a honeypot if the information provided is accurate. If the TSA is encoding the screening level on the barcode, then adversaries can use that information to enhance the success rate of smuggling something past security.

Re:Could be a honeypot

[JWSmythe]

    Actually, nothing.

    If it's a bad guy doing it, they'll have a number trying to go through. The ones with flagged boarding passes will turn around and go home. The ones with clean boarding passes will continue through, smile, and say "thank you" to the TSA people (s)he encounters.

    Anyone with any remotely planned mission will have such things in place, and already be ready for them. Send 5 guys in with tickets. A few will get caught. Some won't. Remember the recent tests where only 25% of the weapons passed through x-ray were caught. 5 people means 1 or 2 will get caught. Those odds can be improved if they synchronize someone who *will* get caught. It will draw attention away from the others who they want to make it.

    I've observed that happening more than once. Someone gets stopped for having something "nefarious", like a bottle of water, or knitting needles. They make noise, more TSA employees go to guard, and now the rest of the lines are understaffed, and more will be waved through unmolested.

Re:Could be a honeypot

[Joe Decker]

Stop it? Don't be silly.

They've added to it.

Re:Could be a honeypot

[Yvanhoe]

Don't overestimate the TSA. Bruce Schneier has the habit of meeting journalists who want to interview him inside the "secure" part of the airport and sending them fake boarding pass to print themselves. He thinks it helps him make his point about how this is all a "security theater".

Re:Could be a honeypot

[cdrudge]

One last thing: Do you know how they smuggle drugs via airplanes?

I just came back from a trip this last weekend. I had a 8 or 10 oz bottle of foot powder in my carry on. It flagged them for a double check. The TSA agent removed the bottle, sent the bag back through, it passed, and stuck the foot powder back in the bag.

I'm no chemist, physicist, or XRay machine technician/operator, so I don't know if a bottle of white foot powder shows up differently than a bottle of cocaine. But I have a feeling it doesn't.

Re:Probably, but watch out for the Audit.

[NIK282000]

There is a very good DefCon talk on youtube about barcodes and how easy they are to scam. It's so trivial to encrypt the data in a barcode but of course TSA has spared every expense in the defence of america.
 
  Here's the DefCon talk: http://www.youtube.com/watch?v=qT_gwl1drhc

Why the hell would you even want to try?

[Anonymous Coward]

These people are lazy. They're annoying, and they're a blight to society. However, for the time being we're all stuck with them until the rest of the general population rises up and says "We've had enough, out you go!".

So I ask you this- even if the system is "easy to game", why the hell would you want to risk it? Maybe you get past their security once, twice, a dozen times, etc. Maybe it is easy to game. That's nice and all.

The question you should be asking yourself is: "What are the consequences of being caught?". These people will happily label you as a terrorist and put you on a no-fly list FOR THE REST OF YOUR LIFE. You think you have legal rights, that they can't do that? They have and they will. Have fun spending the next 5 years of your life debating the finer details of the law in court so you can continue to fly down to Hawaii with the family on occasion for vacation.

It doesn't matter that their system is broken, or that the whole thing is a security theatre and a complete and utter farce. It matters what they're going to do to you when they find out you've been tampering with the system. If you make them look like idiots, their reaction will be to label you as a nefarious terrorist or hacker who was out to get the TSA and thank god they eventually stopped you because who knows what you would have done if they hadn't.

So are you **really** willing to live with the consequences of tampering with the system? Or are you just talking big because someone said the TSA was hackable and now it's all cool and hip to point that out to other people and pretend like you're actually gonna go ahead and do it?

Re:Why the hell would you even want to try?

[dgatwood]

So I ask you this- even if the system is "easy to game", why the hell would you want to risk it? Maybe you get past their security once, twice, a dozen times, etc. Maybe it is easy to game. That's nice and all.

The question you should be asking yourself is: "What are the consequences of being caught?". These people will happily label you as a terrorist and put you on a no-fly list FOR THE REST OF YOUR LIFE.

Which is probably about half an hour for most of the people who would likely be trying to game the system. And that is why it is the responsibility of security researchers and other folks to point out the flaws in the system and to make the TSA look like idiots at every possible opportunity. It is their civic duty, as they represent the only remaining hope that the TSA will either go away or become useful.

Easy to Read, not sure easy to change

[Anonymous Coward]

Look the code to determine pre-check is in the clear and easy to read. What's not obvious is if it's also easy to change. There is a base-64 message below all the normal data that seems to decode to a hash. I would expect that this hash is protecting the integrity of the data above. No one I have seen has modified their barcode and presented it to the TSA. So while there is speculation that it is easy to change, there is no proof and some mild evidence that says this may not be so.

Re:Easy to Read, not sure easy to change

[adamofgreyskull]

Reading that information might be all they need to do. If you have a bunch of co-conspirators on the same plane, you only need one to go through the lighter-screening channel smuggling the box-cutters/drugs/microfilm or whatever; whoever has the magic barcode gets to wear the shoes with the false heels. Alternately, if you know you're not going to be waved through the less-intensive security channel you could cancel your flight or take the flight and just postpone your nefarious deeds for another day.

Boarding Passes with PDF417 barcodes

[Tancred]

My boarding passes seem to have PDF417 barcodes on them. I've tried several but haven't found an Android app that'll read them yet. The Android app from the airline displays a QR code boarding pass, but then I can't scan it with my phone. Anyone know an Android app that'll scan it? Or a program for Mac that'll scan a QR code from the camera? No, I'm not looking to change it, but finding out if I got the PreCheck lane would be nice in advance.

Re:Barcode reading website?

[jibjibjib]

> What century is this?

It's the 21st century. You know, that century where not every Slashdot reader has a smartphone, and the majority of smartphones don't come with a built-in barcode reader, and reading barcodes is mostly pointless enough that the majority of users haven't installed a barcode reader.

Re:looked into it

[Imrik]

Copying and/or modifying is fairly safe, trying to pass it off as the original is when it gets dangerous.

Schneier

[Penurious Penguin]

As usual, a good thread on the topic from Schneier-ville: https://www.schneier.com/blog/archives/2012/10/hacking_tsa_pre.html

Re:Probably, but watch out for the Audit.

[JWSmythe]

    Actually, if they have any common sense, they'd verify the barcode read from the ticket to the barcode stored in the airline DB when the ticket was printed. Modifying it would be a huge red flag.

    But as we all know, the TSA has no common sense. I've considered it mind numbingly stupid that every time I've gone through an airport since 9/11, the super-duper-secure TSA checkpoint (ha!) doesn't check that my boarding pass actually corresponds to a real ticket issued. We're not talking about anything amazingly high tech, except a barcode reader, and network connection to verify against the airline(s) systems.

    The only place that it's cross referenced is boarding, and even that is only most of the airlines I fly. I've been on a few that still just tear the paper boarding pass, and let you on. No verification or anything. At least not before the plane departs. I've been early (just like they ask you to), so I've watched them scanning used boarding passes minutes to hours after the flight leaves. I'm sure we're not suppose to observe procedure, even though it's done right in front of us.

Re:Begin at the beginning...

[tibit]

You can always get a legit boarding pass with no extra screening, change it to extra screening, and see what happens. They can't say you tried to bypass any security measures that way :)