I highly doubt that having root a physical access to a terminal doesn't let you read credit card numbers.
In security, physical access and to a lesser extent root access are equivalent to a guaranteed hack.
In security, physical access and to a lesser extent root access are equivalent to a guaranteed hack.
That having been said, this isn't perfect security. While a chip/tap card is in contact with the reader, it can still be used for fraudulent purposes. And physical access can open the door to other exploits, like trying to break the card's own security or installing a camera to capture images of the card.
How can they verify the transaction details without those numbers?
Your thing in the shape of a credit card is a HSM that holds the private key of the "a certain credit card".
A public key (your bank) can verify if a given digital signature generated by a private key (yor card) is valid or not.
The "CC Terminal" is a device that given the inputs (timestamp+value_of_transaction+password), asks the "CC HSM" to generate the signature of said values. "CC HSM" is smart and will ON PURPOSE refuse to generate valid signatures if you're being funny and inputing wrong passwords. Bank can further check if the signature makes sense or not.
Merchant doesn't need to know the public key, the private key, or your password.
Which makes a hacked terminal problematic since it can display $1.00 as the amount and actually request the CC HSM to sign a $500 transaction.
Because as you rightly pointed out, who said the evil merchant or MitM thief are either MitM'ing the display system, or even have total control of the display system?
A scummy merchant can be banned, a hacked terminal can be removed and examined, etc. And, unlike say a blockchain, a fraudulent transaction can be reversed.
It does, it’s on the right side of the terminal.
https://worldline.com/content/dam/worldline/local/sl-si/docu...
Ideally, the use of these stripes should be completely eliminated, as they can't possibly be secured.
Refunds work with chip insertion or contactless.
I got impression that the chips used to contain the magstripe info, but I hope they removed that when rollout got going.
Already, merchants take on liability for magstripe transactions.
Someone gets their static data skimmed and the card misused? The issuer profits from the chargeback fees...
France was using chip cards since 1992, although with the previous standard.
In my case, the "outer" system was Android, so we could use ADB to control it however we liked--with relatively lax security. The "secure board" only took over for the part where it had to handle payment details. In order to test the payment flows we ended up revamping a bunch of 3D printers to hold a stylus instead because the inbuilt android tools couldn't see or touch anything that secure board was doing except for a relatively narrow set of actions like "start payment flow for $X" and "user canceled" and "payment for $X complete".
The secure firmware can be updated, but it is signed as well.
I'm essentially skeptical that if you have the ability to control the linux root filesystem for a very old linux distro that any other security measures for the linux binaries themselves matter.