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MIFARE Classic: exposing the static encrypted nonce variant [pdf]

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Re: MIFARE Classic: exposing the static encrypted nonce variant [pdf]

#51

Post by pajeets »

jtriangle wrote: post #43
noddingham wrote: post #35

I've been involved with carding for 10+ years and issues with MIFARE Classic cards have been around and known for at least that long. Anyone in the carding industry will (should at the very least) tell you not to use them and move on to DESFire or some other newer safer chips. The introduction even says as much "By 2024, we all know MIFARE Classic is badly broken." If you're still deploying MIFARE Classic cards you r…

"carding" is also colloquially used to refer to people involved in credit card fraud online. Just FYI in case you get weird looks when you say that.

also attracts 3 letters when they see "carding" on clearnet

Re: MIFARE Classic: exposing the static encrypted nonce variant [pdf]

#52

Post by g_p »

madjam002 wrote: post #36

How does this relate to PKCS or cards using PKI? Are there access control systems out there that use this and is it more secure? Or maybe there’s door access control systems out there that use FIDO2 :D

There absolutely are access control systems out there using PKI. For example, the PIV specification (a la DOD CAC) slot 9e is intended for "card authentication" without a PIN typically being required.

PKCS based cards get all the benefits of smart cards (hard in theory to extract keys, side channel resistance, etc), with the usual risks (trust in vendors and issuers to not add backdoor APDUs to applets etc.)

Doubt anyone would want to use FIDO2 for a door access control system, but in theory there's nothing really to stop you, if you come up with a clever URI schema for your doors and know what public key to expect for each identity on each URI. That's where FIDO2 wouldn't be ideal, as you'd get a different identity on each URI, so it would only really work with a single URI (zone?) for the whole site, and implementing zone access checks at each individual verifier.

Realistically, doing a PIV style PKI verification would give you all the benefits of FIDO2, but also with the ability to handle card revocation etc via a CRL that's distributed through the system.

Re: MIFARE Classic: exposing the static encrypted nonce variant [pdf]

#54

Post by corn13read2 »

pajeets wrote: post #51
jtriangle wrote: post #43

Earlier quoted context omitted.

"carding" is also colloquially used to refer to people involved in credit card fraud online. Just FYI in case you get weird looks when you say that.

also attracts 3 letters when they see "carding" on clearnet

3 letters and clearnet in conjunction I’m sure won’t garner attention

Re: MIFARE Classic: exposing the static encrypted nonce variant [pdf]

#55

Post by imroot »

floren wrote: post #29
emag wrote: post #21

Earlier quoted context omitted.

From experience, more places than you'd expect only have you badging in one direction and not both.

But places that actually take access control seriously do implement bidirectional badging, and just opening the door to leave without badging out will send a group of people bearing guns in your direction right away.

You'd think that, but, as someone who did a phyiscal pentest on a prison recently, that's 1000% not the case.

You can set up your access controllers for anti-passback, but, most folks don't, because companies don't want to pay the costs associated for an 'in' reader and and 'out' reader and implement that level of security.

Re: MIFARE Classic: exposing the static encrypted nonce variant [pdf]

#56

Post by borski »

nativeit wrote: post #46
borski wrote: post #20

Earlier quoted context omitted.

Great question; not to my knowledge. There would be many false positives, especially as people bring in guests. Sometimes guests get a temp badge; at many companies, they get a sticker to put on their shirt and get tapped in by their host, who is responsible for them. Rather than building a SOC to look at logs and flag unbalanced entries or similar (which would be very expensive), companies tend to rely on their empl…

I suppose the expense, and the risk in relying on employees, is gonna be quite relative to the organization and its priorities. I wouldn’t imagine setting up a log monitor with some basic monitoring should be that expensive. As someone above mentioned, it’s kind of odd that these systems are so utterly disconnected to the broader IT protocols in so many places. I use a few different RMM solutions that could almost ce…

> I suppose the expense, and the risk in relying on employees, is gonna be quite relative to the organization and its priorities.

Of course. If you work in a SCIF, you're going to have a very different set of rules and experiences than if you work at LiftMaster, if you know what I mean.

> I use a few different RMM solutions that could almost certainly handle the log collection, analysis, and real-time monitoring with alerts and I don’t think it’d take much time/effort to set up.

Right! But someone's gotta watch it. All day, and all the time. If it's sending alerts, who is it sending them to? The same security guard can't be responsible for both watching security monitors and watching or responding to access log issues.

The expense is in the people and maintenance, not in the initial buildout, as is true for many large enterprise initiatives.

Re: MIFARE Classic: exposing the static encrypted nonce variant [pdf]

#57

Post by borski »

imroot wrote: post #55
floren wrote: post #29

Earlier quoted context omitted.

But places that actually take access control seriously do implement bidirectional badging, and just opening the door to leave without badging out will send a group of people bearing guns in your direction right away.

You'd think that, but, as someone who did a phyiscal pentest on a prison recently, that's 1000% not the case. You can set up your access controllers for anti-passback, but, most folks don't, because companies don't want to pay the costs associated for an 'in' reader and and 'out' reader and implement that level of security.

And also pay for the people to enforce it.

Yes, some places do. But those places are rare.

Re: MIFARE Classic: exposing the static encrypted nonce variant [pdf]

#58

Post by borski »

Foobar8568 wrote: post #33
ethbr1 wrote: post #16

Earlier quoted context omitted.

Super curious to know how many common access control solutions flag unbalanced entries/exits. E.g. if "John" badges in... and then 10 minutes later "John" badges in again... Will most systems complain?

I used to work on such systems in another life, we could setup antipass back for a gate or area. I believe we could also put a temporal restriction but my memory is a bit fuzzy.

I don't think the contention was that the feature or ability doesn't exist, but rather that companies choose not to do it. When you worked on those systems - did you set up anti-passbacks?

Re: MIFARE Classic: exposing the static encrypted nonce variant [pdf]

#60

Post by arjvik »

hoherd wrote: post #59
arjvik wrote: post #37

Can I use a flipper zero to perform these attacks?

My guess is NFC -> Extra Actions -> MIFARE Classic Keys -> Add, but I don't have any Classic keys to test on right now.

Oh, the existing MIFARE app already supports this new attack? That's awesome!

I was expecting to have to write some code for it!

I do have a flipper and a classic key, will test it out soon!

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