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Interesting paper on the security of contactless smartcards:
Interestingly, the outcome of this investigation shows that contactless smartcards are not fundamentally less secure than contact cards. However, some attacks are inherently facilitated. Therefore both the user and the issuer should be aware of these threats and take them into account when building or using the systems based on contactless smartcards.
Five stories from Wired.
In related news, IBM thinks it has a solution to the RFID privacy problem:
The so-called Clipped Tag has a notched antenna that consumers can tear off, much like the end of a ketchup packet. Removing this panel drastically reduces the readable range of the device, from about 30 feet to less than 2 inches, according to IBM.
Recent articles about a proposed US-Canada and US-Mexico travel document (kind of like a passport, but less useful), with an embedded RFID chip that can be read up to 25 feet away, have once again made RFID security newsworthy.
My views have not changed. The most secure solution is a smart card that only works in contact with a reader; RFID is much more risky. But if we’re stuck with RFID, the combination of shielding for the chip, basic access control security measures, and some positive action by the user to get the chip to operate is a good one. The devil is in the details, of course, but those are good starting points.
And when you start proposing chips with a 25-foot read range, you need to worry about man-in-the-middle attacks. An attacker could potentially impersonate the card of a nearby person to an official reader, just by relaying messages to and from that nearby person’s card.
Here’s how the attack would work. In this scenario, customs Agent Alice has the official card reader. Bob is the innocent traveler, in line at some border crossing. Mallory is the malicious attacker, ahead of Bob in line at the same border crossing, who is going to impersonate Bob to Alice. Mallory’s equipment includes an RFID reader and transmitter.
Assume that the card has to be activated in some way. Maybe the cover has to be opened, or the card taken out of a sleeve. Maybe the card has a button to push in order to activate it. Also assume the card has come challenge-reply security protocol and an encrypted key exchange protocol of some sort.
Defending against this attack is hard. (I talk more about the attack in Applied Cryptography, Second Edition, page 109.) Time stamps don’t help. Encryption doesn’t help. It works because Mallory is simply acting as an amplifier. Mallory might not be able to read the messages. He might not even know who Bob is. But he doesn’t care. All he knows is that Alice thinks he’s Bob.
Precise timing can catch this attack, because of the extra delay that Mallory’s relay introduces. But I don’t think this is part of the spec.
The attack can be easily countered if Alice looks at Mallory’s card and compares the information printed on it with what she’s receiving over the RFID link. But near as I can tell, the point of the 25-foot read distance is so cards can be authenticated in bulk, from a distance.
From the News.com article:
Homeland Security has said, in a government procurement notice posted in September, that “read ranges shall extend to a minimum of 25 feet” in RFID-equipped identification cards used for border crossings. For people crossing on a bus, the proposal says, “the solution must sense up to 55 tokens.”
If Mallory is on that bus, he can impersonate any nearby Bob who activates his RFID card early. And at a crowded border crossing, the odds of some Bob doing that are pretty good.
More detail here:
If that were done, the PASS system would automatically screen the cardbearers against criminal watch lists and put the information on the border guard’s screen by the time the vehicle got to the station, Williams said.
And would predispose the guard to think that everything’s okay, even if it isn’t.
I don’t think people are thinking this one through.
This is great work by Yossi Oren and Adi Shamir:
Abstract (Summary)
We show the first power analysis attack on passive RFID tags. Compared to standard power analysis attacks, this attack is unique in that it requires no physical contact with the device under attack. While the specific attack described here requires the attacker to actually transmit data to the tag under attack, the power analysis part itself requires only a receive antenna. This means that a variant of this attack can be devised such that the attacker is completely passive while it is acquiring the data, making the attack very hard to detect. As a proof of concept, we describe a password extraction attack on Class 1 Generation 1 EPC tags operating in the UHF frequency range. The attack presented below lets an adversary discover the kill password of such a tag and, then, disable it. The attack can be readily adapted to finding the access and kill passwords of Gen 2 tags. The main significance of our attack is in its implications any cryptographic functionality built into tags needs to be designed to be resistant to power analysis, and achieving this resistance is an undertaking which has an effect both on the price and on the read range of tags.
My guess of the industry’s response: downplay the results and pretend it’s not a problem.
Of course RFID chips can carry viruses. They’re just little computers.
More info here. The coverage is more than a tad sensationalist, though.
EDITED TO ADD (3/16): I thought the attack vector was interesting: a Trojan RFID attacks the central database, rather than attacking other RFID chips directly. Metaphorically, it’s a lot closer to biological viruses, because it actually requires the more powerful host being subverted, and there’s no way an infected tag could propagate directly to another tag.
This Barcelona club requires an embedded RFID chip for VIP status. (Note that the article is from October 2004.)
There’s a good write-up from The Register.
Two points stand out. One, the RFID chip in the passport can be read from ten meters. Two, lots of predictability in the encryption key—sloppy, sloppy—makes the brute-force attack much easier.
But the references are from last summer. Why is this being reported now?
This article talks about a not-a-passport ID card that U.S. citizens could use to go back and forth between the U.S. and Canada or Mexico. Pretty basic stuff, but this paragraph jumped out:
Officials said the card would be about the size of a credit card, carry a picture of the holder and cost about $50, about half the price of a passport. It will be equipped with radio frequency identification, allowing it to be read from several yards away at border crossings.
“Several yards away”? What about inches?
Note: My previous entries on RFID passports are here, here, here, and here.
This is an interesting demonstration project: a hand-held device that disables passive RFID tags.
There are several ways to deactivate RFID-Tags. One that might be offered by the industries are RFID-deactivators, which will send the RFID-Tag to sleep. A problem with this method is, that it is not permanent, the RFID-Tag can be reactivated (probably without your knowledge). Several ways of permanently deactivating RFID-Tags are know, e.g. cutting off the antenna from the actual microchip or overloading and literally frying the RFID-Tag by placing it in a common microwave-oven for even very short periods of time. Unfortunately both methods aren’t suitable for the destruction of RFID-Tags in clothes: cutting off the antenna would require to damage the piece of cloth, while frying the chips is likely to cause a short but potent flame, which would damage most textiles or even set them on fire.
The RFID-Zapper solves this dilemma. Basically it copies the mircowave-oven-method, but in a much smaller scale. It generates a strong electromagnetic field with a coil, which should be placed as near to the target-RFID-Tag as possible. The RFID-Tag then will recive a strong shock of energy comparable with an EMP and some part of it will blow, most likely the capacitator, thus deactivating the chip forever.
An obvious application would be to disable the RFID chip on your passport, but this kind of thing will probably be more popular with professional shoplifters.
Sidebar photo of Bruce Schneier by Joe MacInnis.
