IBM Crypto Up For Grabs?

An Anonymous Coward writes: "BBC Newsnight have tonight shown an article about a groups of hackers who are about to release details of the vulnerability of the IBM Cryptographical processors. ( Details here.) The BBC article can be watched online here. Alan Cox makes a starring role ;)" windowlicker adds some detail: "Mike Bond and Richard Clayton, from Cambridge University, have cracked IBM's 4758 crytoprocessor running the 'Common Cryptographic Architecture' (CCA). You can do the same with $1000-worth of hardware and the info from here. Many banks use this system for protecting PINs." The video file requires Real software; here's the BBC's article online for those of us without.

Comments

RealVideo Coverage

[guru_steve]

I'm watching the video right now, and its taken a bit of time to find out where this segment is on the bbc news.

So, for those of you who don't feel like jumping around the video for this segment, it starts at about 22 minutes in the broadcast.

Insiders

[Embedded Geek]

I'm glad they pointed out that most thefts are perpetrated by insiders (at banks or other companies) due to the other (physical) security measures. I can only hope that other media outlets don't drop the ball on this and start shouting "hackers can steal your cash" on the 6PM news.

Then again... I guess you'd only need to be an insider at the phone company (or whatever company might be leasing a cable to a phone company) to exploit ATM transfers. You wouldn't need to be a bank employee (who undergo background checks, etc).

Question...

[srvivn21]

So they article says that this is really only exploitable by "insiders". At first I felt safe. "Well, at least my money is Federally protected". Then I got to thinking about it. How would I prove that I wasn't the one who used my PIN at an ATM (or several) to clear out my account? Anyone have an answer that can put my mind at ease?
(Not like I'm going to take all my money from the bank, and stuff it in a jar. Just idle thoughts of threat)

Re:Only a matter of time

[WasterDave]

10,000 combinations ~= somewhere between 13 and 14 bits of security. It is entirely feasible for a quick P4 to encrypt every single PIN within an hour, with time left over to play Unreal Tournament.

But if you read their page about how PIN works it becomes aparrent that you still need the derivation key, which is the hard bit to get.

Fake ATMs have been installed in shopping malls, collecting PINs and ATM cards from unsuspecting victims

LOL! Someone did a whole bunch of these in the UK a couple of years ago. Looked and smelled like an ATM, but took the PIN then complained that the card was borked, or something. Easy EASY kill.

because PINless credit card fraud is still so easy.

Exactly. 1e6+1 easier ways of stealing money than opening an ATM with an oxy-acetylene, spending two days cracking it with an FPGA and using all that to hack the banks comms. Easier to just look over some lamers shoulder then pick their pocket. Not that I would know. Not at all.

Dave

Re:Only a matter of time

[Black Acid]

The PIN is four decimal digits = 10,000 combinations ~= somewhere between 13 and 14 bits of security.

For those interested, you can find how many bits a key with x values is using logarithms:

bits = log(x) / log(2), or

bits = d / log(2)

Where d is the number of decimal digits the key is. Therefore, a 4-digit PIN has 4/log(2) or precisely 13.287712379549449391481277717958 bits of cryptographic strength. Not much compared even to weak encryption such as 64-bit DES, or the 56-bit des-ii cracked by d.net.

Re:Lessons to be learned:

[swillden]

Hardware encryption will always be more difficult than software-based encryption to patch when vulnerabilities arise.

Actually this is incorrect. The 4758 is eminently software-patchable because it's a software device inside a secure hardware module. In fact the most difficult and complex part of the 4758 design is the support for secure upgrades of critical software components in a hostile environment. It uses a combination of carefully designed boot stages coupled with hardware interlocks (they call it a "ratchet") that gradually increase the complexity and decrease the access of the software that can be loaded. Thus they start with a miniature boot PROM whose code can be thoroughly proven (in the mathematical sense) to be correct, but whose only purpose is to be able to load the next stage after validating the signature on it. After that second stage is loaded, the "ratchet" is moved and the region of memory that has been loaded is now unwritable. It's very cool stuff, you can read about it in the design whitepaper.

Homogeneity in network environments is nearly always bad. This particular vulnerability wouldn't be nearly as critical if it weren't for the fact that all banks who use these cryptoprocessors either use the same ones or use ones that are similar enough that vulnerabilities like these can be used on more than one "different" type.

I agree in principle, but in practice (1) 4758s are still fairly rare in the banking environment and (2) the reason that the 4758 was an interesting device to attack is because the CCA API is far *more* secure than the APIs provided by comparable devices from other vendors. The authors of the crack paper even mention that they've cracked other devices this way. The 4758 was interesting because it's the best of them.

Note, BTW, that I work for IBM and I know the guys who created the 4758, so I have some obvious biases. I also know my way around the boards :) The real weakness uncovered was not in the 4758, but in a thoughtless patch to the 20+ year old CCA API. The "patch" was the addition of 3DES. CCA is the only (AFAIK) formally-designed API for symmetric key management, and it's really well done. When it was created, though, 3DES was unnecessary. It's now obvious that a little more thinking needed to be done when it was "extended" to support 3DES.

This weakness is very easy to close. I don't know what fix they'll choose to implement, but there's a really obvious and simple one: Don't allow a replicate key part (3DES key with identical halves) to be combined with a non-replicate key part to create a non-replicate whole that is an export key.

What I am certain of, though, is that the entire "patched" CCA API is going to be going back to IBM's cryptographers for formal modeling, so that the integrity of the structure can tweaked until the structure can once again be proven to be mathematically correct. This won't happen again; IBM takes security very seriously and has the people that know how to do it.

While I'm on the subject, Linux freaks will be interested to know that the next-generation OS for the 4758 is... Linux! Well, a stripped-down, thoroughly validated version of Linux, anyway. Dunno if the source will be published or not, but I think so. Linux is already running on the boards, but getting the validated version will take some time.