Author Topic: Hackers Can Now Trick USB Chargers To Destroy Your Devices  (Read 1293 times)

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Offline Halcyon

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Re: Hackers Can Now Trick USB Chargers To Destroy Your Devices
« Reply #25 on: July 22, 2020, 08:44:56 am »
Watch Big Clive, he does several videos on "death-dapters".

He had featured a few mains referenced devices, none were intended to charge a phone.

From memory he did one on a camping light with a "5 volt" USB output which can be used for any consumer devices. He also did one on some coloured Poundland chargers which he ended up blowing up (on purpose).

The point is, dodgy USB adapters exist in the consumer market. I don't recall a single brand-name phone blowing up or having their port destroyed because of it. Many are designed (within reason) to cop what owners throw at them.
« Last Edit: July 22, 2020, 08:47:06 am by Halcyon »
 

Online blueskull

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Re: Hackers Can Now Trick USB Chargers To Destroy Your Devices
« Reply #26 on: July 22, 2020, 08:51:58 am »
I don't recall a single brand-name phone blowing up or having their port destroyed because of it. Many are designed (within reason) to cop what owners throw at them.

When mains goes to your DC-, no phone unless it is plastic cased, can protect the user from being fried. Phone protection circuit protects against differential mode spikes, not common mode.
 

Offline bitwelder

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Re: Hackers Can Now Trick USB Chargers To Destroy Your Devices
« Reply #27 on: July 22, 2020, 08:58:56 am »
https://www.oppo.com/en/newsroom/press/oppo-launches-125w-flash-charge-65w-airvooc-wireless-flash-charge-and-50w-mini-supervooc-charger/


"With an advanced encryption algorithm and strict temperature control regulators, it enables the safe and efficient use of the flash charging device."
Whaaat? Is the encryption algo part of some proprietary power negotiation protocol, or where else does came into play? 
 

Offline Berni

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Re: Hackers Can Now Trick USB Chargers To Destroy Your Devices
« Reply #28 on: July 22, 2020, 09:49:50 am »
From memory he did one on a camping light with a "5 volt" USB output which can be used for any consumer devices. He also did one on some coloured Poundland chargers which he ended up blowing up (on purpose).

The point is, dodgy USB adapters exist in the consumer market. I don't recall a single brand-name phone blowing up or having their port destroyed because of it. Many are designed (within reason) to cop what owners throw at them.

So you expect the phone to have an isolated DC/DC converter inside of it to remain floating even when a crappy chinese mains referenced charger is plugged in? Have you seen the size of isolated switching converters for these kind of powers?

Phones are built down to a price AND formfactor. They have to keep the costs down in the mainstream phones to be competitive in the fierce phone market. Also any high power protection devices require extra board space. With the trend of phones pushing to be ever thinner this space is very limited.

Any decently made phone will survive a lot of static zaps to its USB port, It will survive being charged from a USB charger that is not isolated from mains (But the phones owner might not survive that). But it is not reasonable to expect a phone to survive continuous reverse polarity or 24V on the USB port. Yes it is possible to do it, but might not be worth it. It is the users own fault for using a shitty charger, just like it is the users fault if you put diesel in your gasoline car and complain to the manufacturer when it doesn't run.

But the fact that this hack is possible is indeed horrible design that should have never happened. How fucking difficult is it to get about 2 bits worth of information across a wire reliably.
 
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Offline Syntax Error

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Re: Hackers Can Now Trick USB Chargers To Destroy Your Devices
« Reply #29 on: July 22, 2020, 10:15:36 am »
 :-\ today's old news.

Such is the price for using those ubiquitous public USB chargers. The best counter measure is to use a DC only - or no data - USB lead. And one with a built in limiter circuit.

Today's student design challenge: design a USB charging protection device and lead that is 100% safe to connect to any random public charger point. Whether that USB charger point is on a plane, a bus or attached to a cycling machine in a train station, your design will handle over voltage, over current and, provide isolation from transients, floating earths, etc. Plus, it provides a nice user friendly status LED. Don't cut and paste a design off of Google, figure it out yourself just like your classmates will have to.

 

Offline tom66

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Re: Hackers Can Now Trick USB Chargers To Destroy Your Devices
« Reply #30 on: July 22, 2020, 10:17:21 am »
Today's student design challenge: design a USB charging protection device and lead that is 100% safe to connect to any random public charger point. Whether that USB charger point is on a plane, a bus or attached to a cycling machine in a train station, your design will handle over voltage, over current and, provide isolation from transients, floating earths, etc. Plus, it provides a nice user friendly status LED. Don't cut and paste a design off of Google, figure it out yourself just like your classmates will have to.

There's no such circuit. Say someone designed a USB charging point that was connected directly to 3ph 415V.  No protection circuit is going to protect against that unless it is self-sacrificing.  And then it would need to have a relay/contactor/MOSFET to isolate it and even that has a maximum breakdown rating.
 
There always comes a reasonable limit for which protection circuits are designed to handle.  28V protection on a 5V USB device makes sense because it protects against the worst case of a failed cigarette-lighter charger in a 24V vehicle.  Beyond that point failures are almost certainly intentional.
« Last Edit: July 22, 2020, 10:19:13 am by tom66 »
 

Offline Berni

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Re: Hackers Can Now Trick USB Chargers To Destroy Your Devices
« Reply #31 on: July 22, 2020, 10:32:14 am »
There's no such circuit. Say someone designed a USB charging point that was connected directly to 3ph 415V.  No protection circuit is going to protect against that unless it is self-sacrificing.  And then it would need to have a relay/contactor/MOSFET to isolate it and even that has a maximum breakdown rating.
 
There always comes a reasonable limit for which protection circuits are designed to handle.  28V protection on a 5V USB device makes sense because it protects against the worst case of a failed cigarette-lighter charger in a 24V vehicle.  Beyond that point failures are almost certainly intentional.

Well not to say it is impossible to make a protection circuit that will survive having 400V AC put into it. Its just that the circuit would become unpracticaly large and expensive. Heck you could make a device that survives being hooked up to a 20kV AC transmission line, but the power input connector for that alone would be larger than the phone itself.

At some point the device would become bigger than a USB power bank, at that point it makes more sense to just bring a power bank. It does the same job of keeping your phone protected by preventing you from needing to plug into a unknown source.

But yes id say you could make a protection device that can survive 220V mains put into it that is the size of a disposable cigarette lighter using off the shelf reasonably priced components (Would still take a fair bit of design work tho). Making it work with all of USB-PD would be tougher but probably still possible.

But getting this to fit into the phone itself... ho boy. Good luck with that
 

Offline Syntax Error

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Re: Hackers Can Now Trick USB Chargers To Destroy Your Devices
« Reply #32 on: July 22, 2020, 11:08:17 am »
@tom66 - No need to connect to the device National Grid, just any suspicious USB charger port, such as those on the school bus.

@Berni - This just needs to be a inline box that sits between the charger cable and the target device. It's about the size of a cigarette packet.

Also for your challenge, come up with a catchy name for your protection device.
 

Offline Mr Evil

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Re: Hackers Can Now Trick USB Chargers To Destroy Your Devices
« Reply #33 on: July 22, 2020, 11:52:55 am »
I've not read the specs, but sure it's the fault of the manufacturers. However the USB Implementers Forum (who are in control of the standard) should have anticipated this possibility - after all, the image of the USB PD standard risks becoming severely tainted if this turns out to be a significant real-world problem.

It isn't an easy issue to deal with in the specifications; it's one thing proving a product conforms when operated as intended but how can you prove it continues to conform in the face of an almost infinite variety of possible malign external attacks, especially when in the firmware of the microcontroller in control of the charger?

That is why I suggested that chargers should only be approved where sufficient proof exists that the critical charging voltage negotiations between the charger and the device to be charged and the actual generation of the selected voltage to the interface could only be compromised by physical modification of the product. It would likely add considerable costs and would work to the advantage of the big players at the consumers expense.
Maybe the spec could have been better; I don't know because I haven't read it either. I don't think it's reasonable or even possible to prevent crap hardware from being created though. Consider that the original USB 1 faced a comparable problem with the possibility of damage from connecting two USB hosts together, as they would both try to supply power on the same wire. To prevent that, A-to-A cables were disallowed, and yet that didn't stop manufacturers from creating peripherals with USB-A sockets on them, and A-to-A cables to go with them! They often have the USB logo on them too, despite the logo only being legally permitted on devices that are compliant.

Online blueskull

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Re: Hackers Can Now Trick USB Chargers To Destroy Your Devices
« Reply #34 on: July 22, 2020, 12:03:25 pm »
Whaaat? Is the encryption algo part of some proprietary power negotiation protocol, or where else does came into play?

DRM for liability mitigation. Common in medical consumables industry.

The best counter measure is to use a DC only - or no data - USB lead. And one with a built in limiter circuit.

And having no fast charge capability.
 
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Offline Halcyon

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Re: Hackers Can Now Trick USB Chargers To Destroy Your Devices
« Reply #35 on: July 22, 2020, 12:12:53 pm »
I don't recall a single brand-name phone blowing up or having their port destroyed because of it. Many are designed (within reason) to cop what owners throw at them.
When mains goes to your DC-, no phone unless it is plastic cased, can protect the user from being fried. Phone protection circuit protects against differential mode spikes, not common mode.

No one is talking about the user being fried. This thread is specifically about devices being destroyed.
 

Offline Syntax Error

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Re: Hackers Can Now Trick USB Chargers To Destroy Your Devices
« Reply #36 on: July 22, 2020, 12:20:02 pm »
Quote
No one is talking about the user being fried. This thread is specifically about devices being destroyed.
Maybe place a crowbar mosfet plys a spark gap across the input VUSB/GND?
 

Offline JoeyG

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Re: Hackers Can Now Trick USB Chargers To Destroy Your Devices
« Reply #37 on: July 22, 2020, 01:18:59 pm »
Protection
 

Offline Zero999

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Re: Hackers Can Now Trick USB Chargers To Destroy Your Devices
« Reply #38 on: July 22, 2020, 02:04:15 pm »
All this talk of protection to 400VAC is BS. The maxiumum output voltage of  USB-C is only 20V. It's trivial to design a protection circuit to withstand that. I'd go for overvoltage protection up to 24V, just in case, but that's still easy and inexpensive to implement.
 

Offline Berni

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Re: Hackers Can Now Trick USB Chargers To Destroy Your Devices
« Reply #39 on: July 22, 2020, 07:40:55 pm »
Yeah to be fair 24V does seam like a reasonable bar for protection. But then again something that can handle multiple amps with next to no voltage drop can be pretty bulky, especially when the whole mainboard in a phone is only the size of a few postage stamps.

Also what benefit does the manufacturer get from the extra cost and effort into adding the protection? They expect there users to buy a new phone every 2 years anyway. If a doggy charger that is the fault of the user gets that down to 1 year that's even better.
 

Offline Cerebus

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Re: Hackers Can Now Trick USB Chargers To Destroy Your Devices
« Reply #40 on: July 22, 2020, 08:12:03 pm »
Today's student design challenge: design a USB charging protection device and lead that is 100% safe to connect to any random public charger point. Whether that USB charger point is on a plane, a bus or attached to a cycling machine in a train station, your design will handle over voltage, over current and, provide isolation from transients, floating earths, etc. Plus, it provides a nice user friendly status LED. Don't cut and paste a design off of Google, figure it out yourself just like your classmates will have to.

There's no such circuit. Say someone designed a USB charging point that was connected directly to 3ph 415V.  No protection circuit is going to protect against that unless it is self-sacrificing.  And then it would need to have a relay/contactor/MOSFET to isolate it and even that has a maximum breakdown rating.
 
There always comes a reasonable limit for which protection circuits are designed to handle.  28V protection on a 5V USB device makes sense because it protects against the worst case of a failed cigarette-lighter charger in a 24V vehicle.  Beyond that point failures are almost certainly intentional.

You've obviously never heard of load dumps.
Anybody got a syringe I can use to squeeze the magic smoke back into this?
 
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Offline tom66

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Re: Hackers Can Now Trick USB Chargers To Destroy Your Devices
« Reply #41 on: July 23, 2020, 06:30:31 am »
You've obviously never heard of load dumps.

Of course load dumps are a thing, but you'd be having a remarkably bad day if you happened to have your device connected to one while a load dump occurred, while the charger was short circuited and malfunctioning, and the charger had no load dump provision at all on its input.

The point is you need to stop at some point and engineering a phone to survive 120V from a 28V load dump given it normally charges on 5V is not going to be easy. Maybe it is something an industrial smartphone could do.
 

Offline Berni

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Re: Hackers Can Now Trick USB Chargers To Destroy Your Devices
« Reply #42 on: July 23, 2020, 04:13:35 pm »
I think its more the case that a load dump would blow up a cheap cigarette socket USB charger since most are not all that well made. And the failure mode of buck DC/DC converters is often to just let the full input voltage trough. Still a load dump is rather rare is likely to fry something else too.

But yeah its ridiculous to try and design a phone to handle that. I do think it would make sense to survive 24V if you have a USB-C port on the phone. But i can see why a lot of phone manufaturers wouldn't bother with the extra cost and the effort to find room inside the phone for an additional bulky power IC.
 


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