You could then separate the audio system from your car and drive around with a boombox

Well, that's what we all did like 10-15 years ago with nice double-DIN decks that had nothing to do with the car besides taking power from it and perhaps some steering wheel controls. It was just a hard-wired boombox, 100%. Now, the stereo is in fact properly a part of the Infotainment System you cannot replace, so as it ages out in a perfectly good vehicle, the entire car deprecates faster than it would have in decades past.

Even my 2015 Mazda has enough vehicular settings in the infotainment menu that despite being replaceable with a double-din I haven't bothered because I'd lose all configurability there. I opted for a cheapo $100 carplay unit instead - the modern equivalent of the discman-to-tape adapters ;)

Difference is a plastic card that is lighter and smaller than the phone is just as effective as the phone is for payments. When it comes to audio, a car stereo is going to be much more convenient and brtter quality than a boombox or bluetooth. That said, i did know someone with an older car who used a bluetooth speaker instead of their stereo, so they could connect their phone audio.

I don't know about where you live but here contactless card payments have lower limits than phone-based ones. Also the phone allows me to switch between multiple cards, including transit-specific cards.

In the US IME there are not restrictions on card spending that are a barrier. In UK I had to sign for a purchase over £100. Extra 10 seconds.

In UK, my credit card was my transit card. I find it easier to navigate my physical wallet than a phone for such things. Personal opinion.

In any case, banking apps that don't function on graphene should be embarrassed by their stupidity. Amex forces sms/email 2fa to login on my graphene phone, when chase, fidelity and several other bank apps do not.

I forget. What are the security implications of having your car play your music again?

Pretty sure Jeep was hacked via their infotainment system and remotely driven (by researcher Charlie Miller)

So it’s actually kind of a real thing

I'm pretty sure that the infotainment hack was completely orthogonal to whether it was Beethoven, Iron Maiden, or blissful silence.

Having said that, a successful car infotainment system attack on android auto or apple carplay could, of course, compromise your phone.

So it's up to you whether you decide to cope with that possibility by breaking the law and navigating with a handheld device, or simply declining to do banking on your phone, since successful car exploits mean the attack surface against your phone is much larger than you might presume.

> separate the audio system from your car

I was responding to a comment about the security implications of letting the infotainment system interact with the vehicle controls, and I referenced an incident where someone compromised a car via that.

I have no idea how CarPlay would compromise your phone given apples sandbox but whomever finds it is gonna have a multimillion dollar payday since iOS jailbreaks are quite valuable.

The initial convo went:

> Paying with your phone just seems like one of those separation of concerns problem.

Followed by:

> You could then separate the audio system from your car and drive around with a boombox

The first discusses behaviors of end-users. The second was a lame attempt to take the mickey of that, which is why my response clearly indicated that, to my knowledge there are zero security implications of playing your music through your car's entertainment system.

This remains true.

You are discussing design flaws, not user behavior flaws, which is why I pointed out that the design flaws you bring up, in addition to doing you bodily harm, could conceivably also be part of an exploit chain that validates the original poster's concern about using his phone for banking.

But I still sincerely doubt that the choice of playing Beethoven or Iron Maiden either directly places you at risk*, or makes a difference to the ease of exploiting any design flaws in your vehicle.

IOW, the first behavior given (not using your phone for banking) is easy to construe as prophylactic, given that, yes, in fact, peoples' credentials have been stolen from their phones and bad things have happened, due to using phones for financial transactions.

The second behavior given (use a boombox instead of your car's audio) of course could theoretically alter outcomes, but to my knowledge, there has never been a car exploit that depends on whether you have fiddled with the volume control or station selector.

* Assuming of course, that your volume isn't so loud that you've riled up other people. That's always a risk.