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Comment by Jiocus | Hacker News Reader

The author mentions "military grade firewall", as a must have in a vehicle. Genuine question; What's a military grade firewall?

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As someone who has been working in security for past 10 years and systems / network admin for another 10 before that, I don't even know what a firewall is supposed to be any more.

Also, since I've worked on military systems a lot, I suppose a military grade firewall is just iptables for which someone has written a shitty gui (that might as well just be a webshell) and packaged it into a green rugged box.

A stupid requirement.

Consider this. Almost every car on the road today has an unsecured bus going back to like the 1980s. However you need to actually access the car to do something malicious so the threat vector is zero; since if you have access to the car you can also just cut brakes or put in a pipe bomb.

The only reason why this paradigm changes in the EV era is because the insistence on having EVs phone home. Now you can concievably hack all EVs of this model at once and that is now realistic and even attractive to do. But again not a necessity for running a car. Just something that modern software focused companies want to see that leads to a host of expensive security issues that didn’t exist before. The car could be airgapped with the dealer network used to flash software updates like they do with most other cars before EV era.

The threat is not exactly zero. In some cases, thieves can get physical access to the bus from outside the car, and then inject messages to unlock it, start the engine, and drive away: https://kentindell.github.io/2023/04/03/can-injection/

Sure someone in that situation could also "just cut brakes or put in a pipe bomb" but car theft is a lot more common than assassination, at least where I live.

There are plenty of cars on the road today where theft is as easy as splicing two wires together. And yet grand theft auto isn’t very common at all even with all of these cars capable of being stolen in 10 seconds are being parked unsupervised on just about every block. Seems there are other filters in the overall system of society that are effective in keeping these unsecured cars from getting stolen today.

> Almost every car on the road today has an unsecured bus going back to like the 1980s. However you need to actually access the car to do something malicious

See [1] from 2023, where popping the headlight gives access to the bus. Lack of internal security then gives a way to steal the car.

The threat just isn't the same as the one you are modeling.

Security will come eventually, if only to prevent bad publicity.

[1]: https://arstechnica.com/information-technology/2023/04/crook...

ETA: Just as the sibling says...

It begs to ask why a headlight ought to have a data connection and not just power connection like most other cars of say 20 years ago. But even then when does the arms race end? Someone given enough time can cake apart a car to access any piece of it. A slim jim gets you to the hood release and the ecu of a say 2000 honda civic in 20 seconds. Was this a real world issue however in the 2000s, people hacking into drive by wire early obdii era cars like the s2000 to assassinate them with misdirected inputs or whatever the threat vector might be? Not really. Old fashioned ways to screw with people are simpler and cheaper.

> The car could be airgapped with the dealer network used to flash software updates like they do with most other cars before EV era.

I would rather have OTA updates than enable parasitic middlemen to siphon money out of me

A firewall built by the lowest bidder, that barely functions, but is robust to even bored Marines deciding to play with it.

I think anybody using this term has a shallow understanding of network security and just bundles it all mentally into a “thing” that stops all the bad stuff from happening.

I know that "military grade" has some relevant distinction in automotive. For example, normal car parts are designed to withstand "up to 80°C" and military grade means "up to 120°C". That has an impact on material choices and cooling.

No clue about firewalls though.

One of the most fun things I’ve done as a white-hat pentester was making a moving train open its doors at 60km/h, over CAN, from 6000km away.

I don’t know what constitutes a “military grade firewall” but presumably something that stops that. Or at least tries to.

Such a thing exists though usually not called “military-grade” per se. It is more similar to a data diode [0] than a classic firewall but has significant differences from either.

Data streams are converted into a sequence of objects that are required to have and satisfy certain formally verifiable properties as a pre-condition of forwarding. Any data or objects that cannot satisfy formal analysis requirements are dropped. Forwarding policies are only applied to objects that meet the prerequisite of being rigorously analyzable.

This behavior is bidirectional. It applies equally to data egress to mitigate internal threats and accidental data leakage. The internal mechanics can be pretty complicated and they necessarily operate on a store-and-forward basis. The data objects may be “laundered” by the firewall, what you send may not be exactly what the other side receives.

To make this work, the wire protocol, data representation, etc must be designed specifically to allow this kind of rigorous analysis and work well within these constraints. It usually won’t work on a random web stream and the data representation often sacrifices efficiency of storage for efficiency of verification and analysis at runtime.

In reality, virtually no one uses this type of tech outside of defense and intelligence because it won’t let almost any of the standard web stack slop through.

[0] https://en.wikipedia.org/wiki/Unidirectional_network

Ah, yes that's true. I had actually forgot about this type of thing (did study infosec at uni)

An idiom meaning strong and resilient.

I wonder if that is a "Genuine question"..

"military grade" is often used as a marketing term used for things that pretend to be built to be extra strong.

In this case it is a stupid term to use to describe a firewall cause a firewall either works or it does not.

I guess it's the same as a 'bulletproof firewall'. Just a colloquial saying indicating both high importance and required quality expected for operation in strong adverserial environments.

https://en.wikipedia.org/wiki/Radiant_Mercury

Helpful article, thank you!

a firewall that prevents someone getting direct access to CAN bus and ECU, and sending messages like: "Key present", "Engine start", just by connecting to the wires of the headlight lamp (by prying a fender next to headlight)

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