Video: Power LED Attack [video]

Re:Video: Power LED Attack [video] by rolandog on Sunday July 02, 2023 @07:11AM (#36560337)

    // TODO remove ductape; temp fix of https://ia.cr/2023/923

Edit: Joking aside, capacitors and black tape are actual countermeasures:

    Fig. 15. A circuit that leaks information via its power LED (a). Counter-
    measures using a capacitor (b), an additional OPAMP (c), and an existing

OPAMP (d).

And:

    Consumer Side Methods. The attack can also be prevented
    by placing black tape over a device’s power LED.

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Re:Video: Power LED Attack [video] by jacquesm on Sunday July 02, 2023 @08:56AM (#36561049)

or just snipping it.

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Re:Video: Power LED Attack [video] by TedDoesntTalk on Sunday July 02, 2023 @10:15AM (#36561682)

Or simply manufacturers not using LEDs to indicate activity.

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Re:Video: Power LED Attack [video] by sokoloff on Sunday July 02, 2023 @10:32AM (#36561828)

This is not an intentional indication of activity, but rather just of power.

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Re:Video: Power LED Attack [video] by jacquesm on Sunday July 02, 2023 @12:52PM (#36563240)

They don't. The LEDs fluctuations are a by-product of power rail fluctuation and this in turn can be detected to discover some elements of the computations involved.

It's pretty subtle. This isn't like a flashing harddrive LED, it is an LED that to all intents and purposes is burning steadily. Until you look at it in more detail and you realize that it isn't quite as steady as it should be.

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Re:Video: Power LED Attack [video] by qingcharles on Sunday July 02, 2023 @11:26PM (#36568381)

I'd at least solder another diode across the terminals if I did that. An LED is a diode at the end of the day and breaking the circuit might break the device.

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Re:Video: Power LED Attack [video] by jacquesm on Monday July 03, 2023 @04:10AM (#36570166)

Not if it is just a power LED. No circuit that I'm aware of would break if the power LED wasn't drawing power. You'd have to go out of your way to make it that way.

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Re:Video: Power LED Attack [video] by qingcharles on Monday July 03, 2023 @08:51PM (#36580768)

Thank you for the clarification. I've not soldered anything for a couple of decades so my knowledge is poor.

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Re:Video: Power LED Attack [video] by jacquesm on Tuesday July 04, 2023 @02:01AM (#36582754)

I did think that your approach is very thorough, 'change nothing' is a good principle.

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