Slashdot Mirror
The Rising Barcode Security Threat
eldavojohn writes "As more and more businesses become dependent on barcodes, people are pointing out common problems involving the security of one- or two-dimensional barcode software. You might scoff at this as a highly unlikely hacking platform but from the article, 'FX tested the access system of an automatically operated DVD hire shop near his home. This actually demanded a biometric check as well, but he simply refused it. There remained a membership card with barcode, membership number and PIN. After studying the significance of the bar sequences and the linear digit combinations underneath, FX managed to obtain DVDs that other clients had already paid for, but had not yet taken away. Automated attacks on systems were also possible, he claimed. But you had to remember not to use your own membership number.' The article also points out that boarding passes work on this basis — with something like GNU Barcode software and a template of printed out tickets, one might be able to take some nice vacations."
> The article also points out that boarding passes work on this basis -- with something
> like GNU Barcode software and a template of printed out tickets, one might be able
> to take some nice vacations."
Yeah, in Guantanamo...
Great, now GNU Barcode will be classified as a terrorist weapon...
Think about this: you go somewhere that uses ID/membership cards with barcodes on it. Salesdrone asks for your card. If you just give them the number verbally and are security-minded, they'll probably ask for ID. However if you provide the card, they won't, because they the card *is* the ID.
Non-technical people don't understand how barcodes work, so they assume that nobody else does either. So if nobody else understands it, then it can't be forged.
Darn it, now Acme* is going to read this and put a stop to my fake-discount-card ways. (they'll accept any code with the right length and first three digits... amusingly including other supermarket's cards).
*That's the grocery store, not Roadrunner's coyote-torturing company.
There is nothing special or inherently secure about barcodes. They are just a machine readable number. Security has nothing to do with it- those are measures taken outside the barcodes. Anyone can print any type of barcode on just about anything.
Being able to print 2-dimensional, 3-dimensional, or even n-dimensional barcodes is useless no matter what software you have unless you already possess the inside info of knowing somebody's valid account number, data, etc. If somebody's gotten a hold of enough info to successfully print and use an illicit barcode, your security problem lies NOT with the barcode itself but with the system that allowed this information to get out in the first place.
The same situation exists with magnetic stripes. If you have valid account data you can write it to a magnetic stripe on a card and go to town with it. It's getting the data that's the hard part.
Sounds like the brilliant utility companies of the '60s that trusted the billing and payment amounts that they sent to their customers on punched cards, and expected to trust when the cards were returned with "payment".
I used to work at a semiconductor fab - basically a big chemical factory. Access control, security and timecards were all kept by a barcode system, printed on the back of your badge. I had a lot of fun making bar codes to see which would get me into places I shouldn't have been, like the spaces between the cleanroom walls, or the tunnel under the building, or the chemical storage area (that was a place I didn't ever like being in). Probably seems worse now than it did then.
Back in elementary school we had a stored-value system for buying lunch, with security based on bar codes on little plastic cards. This was nearly 20 years ago and there was free software available then (on my Commodore 64? Atari? Can't remember) to generate bar codes. I made a couple, based on the ID numbers of friends, and gave them to the lunch lady, telling her that those cards were a bad idea. They never changed anything, though. These days I'd have been kicked out of school for that, though, if not arrested.
Just my $0.55 (US inflation, 1774-2008, for $0.02)
I remember reading about some guy who was stealing using bar codes. He would go to a store, and put a fake price sticker complete with a fake barcode on some expensive item; then he would take the item to the cash register, where the sales person would scan the bar code, the item would ring up as something less expensive, and he would pay the amount on the cash register. Sell the item at a large profit, then repeat.
He made up the fake stickers at home. I believe he would buy one of the less-expensive item, and at home he would duplicate its sticker. He didn't even need to generate the bar code, he was just copying the one that was on there.
Eventually he did the same trick too many times and they caught up with him.
If anyone remembers details of this story and can post a link to it, please do.
steveha
lf(1): it's like ls(1) but sorts filenames by extension, tersely
L33t hackers discovered that with a certain amount of awareness and bravado it is possible to obtain quite tasty sandwiches for free, by hanging around the pickup counter at sub shops and pretending to hold the ticket number that was just called out.
When self-checkout machines first appeared in groceries I thought of this one.
1) Go to your nearest grocery store that has self checkout machines as well as a weigh station in the produce dept.
2) Pick up an expensive bottle of wine.
3) Go to the produce section and put the wine on the scale and enter the code for a cheap item such as potatoes.
4) Place the printed barcode sticker over the barcode on the wine bottle.
5) Pay for your items using the self checkout. The machine verifies all purchases by checking the weight in the bagging area - which of course will match perfectly.
As an added bonus for those under 21, you will not be carded for your alcohol purchase. Of course I would never do this, but I can't imagine that I am the first person to think of it.
Anyone who has done any work with barcodes knows they are encoding schemes, not encrypting schemes. A barcode is simply a way of representing data (may be alphanumeric or binary), in a way that is easily read by scanning equipment. The commonly used algorithms are well publicized and it is easy to obtain software to read or write them. If security is important, encryption must be applied before the data is encoded in a barcode. I've scanned many barcodes on many things, and if money is involved, such as tickets or postage, I've generally found that they decode to seemingly random binary data, which means that most likely, encryption was applied first.
If I can be modded down for being a troll, can I be modded up for being an orc, or a balrog?
The talk this Heise article is about (which was held at 24c3 on friday) is actually available as a full-length download in various formats on mirrors (look for "2273-en-toying with barcodes") and on bittorent along with most of the other talks given at this (totally awesome) event. And it's in english, too.
I've done this for kicks just to see if I could do it, but once I brought one of my fake ID's and fake boarding passes to the airport and got through the "security" (security? BAHAHAHA!) and made it into the terminal. Bought some drinks, ate some food and went home.
:P
No one was the wiser.
You see, it's just a billion dollar FARCE and a WASTE OF TAXPAYERS MONEY for the *feeling* of safety when there really isn't any.
Of course I couldn't get on the plane. I couldn't get on a plane in 2001 without a correct ticket anyways. They had the barcode scanners to "check" you into the plane anyhow. At least, I remember them being available back in 1999 -AND- I wasn't too keene on getting onto a plane where there weren't enough seats where I'd get caught
Anyways, just as I said, this is easy to blow a hole through. There's nothing in the world that makes me more mad than being patted down, scanned or searched before boarding PUBLIC TRANSIT. I'm not a criminal, wtf are government agencies doing there?
(posted anon and through a couple anon proxies)
http://ftp.uni-kl.de/24C3/matroska/24c3-2273-en-toying_with_barcodes.mkv
:-D
See this website for mirrors, other video formats and the rest of the videos of the 24C3-conference (some of them are really interesting, videos with a 'de' instead of 'en' in the filename are in german). http://events.ccc.de/congress/2007/Conference_Recordings
Happy new year, gentleman/women
Once, I got on a flight to Hawaii. The plane was about to push off and, like most of the other passengers, I had settled into my seat. Then some other passenger came and said I was sitting in her seat! We compared boarding passes, and lo and behold, both of our passes were for the same seat! We couldn't figure it out, so we asked the flight attendant for assistance. She couldn't figure it out either, so she had to go back to the boarding gate with our passes to ask the ground crew to figure it out.
After a while, someone finally realized what happened. I was on the wrong flight! I was on board a direct flight to Hawaii, but I had actually bought a ticket to fly to San Francisco and from there transfer to a flight to Hawaii. I had always thought of it as "my flight to Hawaii" and had completely forgotten that I would have to transfer. The boarding gate was off by one, but the airport always changes boarding gates at the last minute and I figured this was one of the times. And the flight was scheduled 5 minutes before my actual flight, so I figured that the flight was early. I lined up like everyone else with my Internet-printed boarding pass, the computer scanned it, and I got on board just like everyone else. There was no alarm that I was on the wrong flight or anything like that.
That was with me accidentally getting on the wrong flight. What do you suppose could happen if someone was intentionally trying to pull off a deception? The only redeeming feature is that this happened in 2002, and I hope that airline security has improved somewhat since then. (I can dream, can't I?)
404555974007725459910684486621289147856453481154 in hex is "You sank my Battleship?"
[GPG key in journal]
Hmm. I boarded a flight on Dec. 24, sitting in seat 27C. As I got on the plane and handed the ticked to the member of cabin crew (having already had this boarding pass scanned at least twice) for her to direct me to my seat, she pointed it to me, and then did a double take.
"Sorry," she said, "I thought your ticked was for December 27, not row 27."
Now, either she was tired, or that's something that happens sometimes. Anybody know?
The article also points out that boarding passes work on this basis -- with something like GNU Barcode software and a template of printed out tickets, one might be able to take some nice vacations."
What if the rightful owner shows up with the same ticket number? Unless the tracking software is lame, it should note that a given number had already check in. At that point, an investigation would ensue. The perpetrator is probably caught on camera for non-trivial travel and the time stamp of check-in and the camera would identify the crook.
Table-ized A.I.
Keep dreaming.
My experience with a current construction project for a major airline at a major airport speaks to a discomfortingly confused security situation.
The first time I went to the site with the Architect, who had a badge to escort us into the terminal, we were refused entry at 3 different points, always told to go somewhere else that wouldn't let us in. Then we went to an airline official, who said that the badge the architect had would get us in at a security gate that we tried before, so she escorted us there, and we weren't let in. So she did about a half hour of research, and found that we needed to go to the desk where they check in pets in their crates! There they checked the architect's badge and our IDs and issued us each a ticket-like piece of paper that we took to the security gate. There they took that "ticket" from us (and my co-worker's zippo lighter) and let us through. We then had the run of the place, without any ticket or pass.
We spent over an hour and a half getting in to do 2 hours of work. Then, after suffering through all that security red tape, we at one point got separated from the contractor with the keys, while we were in the non-secure loading dock (accessible from a public roadway). But not to worry, a friendly worker let us back to the secured passenger terminal side.
The second time I went with my boss, who picked up his own badge that he applied for three weeks earlier. He had been told it was ready to pick up. It took a little over an hour wating in lines and watching safety videos to pick up the badge. But when we tried it (it was a swipe and pin number type), it didn't work. So we went back down to the security badging office, only to find a sign on the door saying that they were closed for lunch and would be back at 1:00pm (even though it wasn't noon yet). I went back to the office, and he stayed the rest of the day to get it straightened out and do about an hour of work.
The third time I went, construction was well under way, the walls were knocked down, and the only thing bewteen the public parking and the secure air side was some pastic sheeting.
Did I mention that both the existing layout and the new design include a loading dock that connects the non-secured public roadways with the secure airside through a locked, but un-manned, door? Anyone on the inside (including employees, or sneaky passengers) could open the door, (or man the freight elevator if they had the key), and bring large, explosive things off the truck with a forklift and into the passenger terminal.
I don't see much to be concerned about. "Hacking" them isn't really new, switching UPC stickers has occurred for decades, and as mentioned by another reader, it's considerably small instances. The best place to put security worries is in the bar-codes offshoot, RFID tags.
...is the Trojan zebra camouflaged within.
I find it a bit surprising that no one's yet mentioned the free 3of9 barcode font .
Back when I had a working scanner / OCR setup, I spent a lot of time trying to reverse-engineer the barcodes on coupons. You might be surprised how lenient cashiers are with those things these days... even after a former co-worker of mine printed up (and handed out) about 1,200 self-made "Free 20oz Coke Product" coupons.
With internet-printable coupons more popular than ever, I wonder how long it'll be before we start seeing larger-scale scams involving reverse-engineered "custom coupons"?
I don't suffer from insanity, I enjoy every minute of it! --Longbottle