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Break Me If You Can: Exploiting PKO and Relay Attacks in 3DES/AES NFC

Looks awesome! I see some Flipper Zero apps were already created. When will you be releasing this for the Chameleon? Also, any plans to port this over to the Proxmark?

2 hours agoarkwin

All of the attacks are released for the three platforms (Proxmark3, Flipper Zero, and Chameleon Ultra). Our goal was day 1 support for RFID testing devices.

2 hours agonoproto

3DES has been broken for a decade. Nice job putting it all together though.

2 hours ago1970-01-01

> Is this a flaw in the cryptography itself? No. The underlying cryptographic algorithms (3DES and AES-128) remain secure. The vulnerabilities arise from:

Protocol design choices that allow unauthenticated memory writes after initial authentication Lack of atomicity when writing cryptographic keys across multiple memory pages Widespread misconfiguration in real-world deployments (unlocked memory, static keys) Non-NXP compatible chips with severely flawed random number generators

33 minutes agomoribvndvs

It has? What exactly do you mean by that?

2 hours agotptacek

It means you should not use it for anything important, because it can be decrypted by the public with little effort. If you look back, it has been this way for quite awhile. My gripe is with the clickbait title 'Break Me If You Can'

https://nvd.nist.gov/vuln/detail/cve-2016-2183

an hour ago1970-01-01

BREAKMEIFYOUCAN! is the default factory key programmed into every MIFARE Ultralight C chip by NXP.

29 minutes agotostrstrudel

How exactly would you decrypt a 3DES ciphertext "with little effort"?

an hour agotptacek

if i were to guess, they are referring to CVE-2016-2183, which lead to deprecation of 3DES by NIST in 2019 (announced in 2017) and disallowing all uses in 2023. openssl also stopped including it in default builds starting in 2016 because it is considered weak.

2 hours agozxcvasd

This is Sweet32, an attack on any block cipher with an 8-byte block size. We don't consider those ciphers "broken"; they just can't be used safely in some common modes. You shouldn't use 3DES or IDEA or Blowfish, of course, but I don't think they're considered "broken", not in the same sense that, say, RC4 is.

2 hours agotptacek

It's true that 64 bits was known not to be enough when DES shipped decades ago, but there is some difference between "We know that's a bad idea" and a demo showing why, and so I think I'm OK with the word "broken" in that context.

There's a reason POCs matter right? Why you feel comfortable (even though I don't agree) saying multi-threaded Go doesn't have a memory safety problem and yet you wouldn't feel comfortable making the same claim for C++.

an hour agotialaramex

This semantic argument was more plausible before the original commenter claimed 3DES can be "broken with little effort".

an hour agotptacek

I'm not a cryptographer but to me "broken" seems to imply that the core algorithm itself can be attacked. If merely applying it in certain ways as part of some larger system can fail then aren't most (possibly all) ciphers broken? It's entirely possible to do all sorts of stupid things.

Granted, a 2^32 block limit is pretty severe by modern standards.

an hour agofc417fc802

Not to be rude, but it seems to me that you are engaging in some hairsplitting. In general, security people do not recommend to use 3DES or RC4 - even if RC4 is broken in other ways than 3DES.

8 minutes ago_tk_

to any non-cryptographer, i think that's a distinction without a difference. it's disallowed from use by the major standards institute due to a vulnerability where people can recover the plain text.

that sounds "broken" to me, but i'm not a cryptographer. so, i'll defer to you when you say it's not broken. (i dont know what the cryptographer-specific definition of broken is -- it'd be great if you would shed some light on that)