EMV Broken by Inventing Card Response

EMV user verification uses several methods, one of them is a PIN entered by the user. However, please note that this proves the user identity to the card, not to the terminal. If no-one checks the security state of the card, this is pretty pointless. They simply catch the verification request sent to by the terminal to the card, throw it away and reply with a code that means "PIN was OK".

So what now? Actually, the responsibility for a correct transaction is with the merchant, because only the merchant has at least a possibility to ensure a correct transaction: If a proper terminal is used and there is no strange cable coming out of the card (see the video on the linked page) the transaction is still good. However, the damage goes to the customer, not the merchant.

And, of course, there is a huge hole in the protocol.

There is only one way to do it properly:

• User enters PIN
• Terminal asks card to sign the transaction
• card signs the transaction if and only if it has received the correct PIN

And everything done with mutual authentication end, message confidentiality and message integrity.

Where is the problem with this? It requires chips that are a little more expensive than the most simple ones. It's called "dynamic data authentication"and "Transaction Cryptogram" in the EMV world, but unfortunately it is not used in this case.

Identifying PCs by Browser Settings

My browser fingerprint, as determined by panopticlick in a project started by the Electronic Frontier Foundation is currently unique under approximately 500000 browsers. Most of the identifying information comes from browser plugins and installed fonts - my font set alone makes my browser unique. To be more precise, my browser sends out 19 bits of identifying information.

To make things worse: you can even deduce someone's affiliations from the installed fonts to target spearfishing attacks. Big companies as well as political parties like to use special fonts to generate an unique look in their documents.

I get identical results for safari, firefox and chrome. Switching off javascript reduces the amount of information available to the identificator by 3 bits.

The lowest result I get is for my iPhone: only 11.02 bits of information. It would seem to me that most iPhones look equal.

The Missing Bus Error

Apple was slammed for not fixing an exploitable bug. That made me curious and I compiled and ran the following:

#include
#include

int
main()
{
char s[]="111.111111...11";

float a=atof(s);
printf("%f",a);
}

which is said to cause a bus error. However:

Opportunity:misc ullrich$ gcc -o buserror buserror.c
Opportunity:misc ullrich$ ./buserror
111.111115Opportunity:misc ullrich$

on my trusty MacBook, which looks more like a rounding error to me. Maybe they just fixed it - I use 10.6.2

Why not simply use explosive-sniffing dog?

In the aftermath of the failed attack on the Delta 253 flight everyone calls for new technologies which may be quite intrusive and certainly are very expensive. So, I'm wondering why don't we use explosive-sniffing dog at the airports? These animals can find even smallest quantities of explosives. Even bees can be used to search for explosives.

Legic Prime Has No Cryptography at All

This is really weird: Karsten Nohl and Hendryk Plötz have shown that the Legic Prime contactless smart cards neither a random generator nor an encryption algorithm. Users of Legic Prime are recommended to upgrade to Legic Advant which contains AES and is compliant to FIPS 201.

Heise article (german)

GSM Security Broken, Finally

It was well known for a long time that A5/1, the GSM encryption code is not secure. Now it has finally been broken. Nobody ever believed that our phone calls were safe from the secret services of this world. The issue is that now the calls and, even worse, SMSes are vulnerable to criminals, too. This is a problem M-TANs are used in online banking, for example.

But not all is lost: UMTS uses another algorithm, called MISTY or KASUMI, which is still considered safe. So, use M-TANs only if you have a 3G uplink.

Credit Card Abuse, Again

Employees of a call center in Bremen, Germany allegedly have abused the credit cards of customers of British Airways. This has been reported be the TV magazine "buten un binnen". A team manager has been arrested. Certainly this is only the tip of the iceberg.

It is well known and accepted that credit cards offer no security all. Users will reclaim their money, if they read their credit card statement. Fraud costs will be distributed to the general public via insurances and merchant fees.

However, a normal smart card won't fix this because it can't be used with a call center. The only viable options here are the internet with secure online banking and OTP. Both options require that dedicated security hardware is used by the end customer. There is no free lunch.