That is a smart idea. However, I was looking for a small device which could be attached. Perhaps there is a way to trick the internal heat sensor into believing it is too hot? If you can think of a small hand held device which can achieve this I would be fascinated. @hamena314

The thermal cutouts in such devices are intended to preserve the lifespan of the component if it generates too much heat. Those components are designed to withstand far more than the surrounding ones. If you're heating the entire device to the point that the thermal cutout engages, you've already killed the rest of the board and other components.

If the motherboard is exposed you could try to point an laserpointer? Concentrated ammounts of light are known for producing heat. But the laser has to be class 4 I think.

@JozefWoods I have had a computer overheat and shutdown before without breaking? Regardless, if heat is applied roughly to the part of the device which contains the sensor would it help? I can't comment as to how protected our product is against heat sadly.

@Bomskie Sadly it is protected by a case. Sometimes I might roughly know where the heat sensor is, but in other models I would be unsure. Also wouldn't a class4 lazer damage the board if I missed? :P

@JozefWoods: You dont need to heat the whole computer above a certain point. If you blow hot air into the computer case, the fans of the CPU would not be able to transfer the heat away from the CPU fast enough, therefore the heat-sensor on the motherboard will at least reboot the computer or even shut it down.

@k1308517 Yes, but not from heat external to the device. Improper cooling means that it can't get rig of the heat from the device. We're talking about doing something to the outside of the device to heat it to the point of thermal cutout. Without being able to target the CPU/GPU, you'd cause damage to surrounding components long before topping off the CPU.

@k1308517: "If you can think of a small hand held device which can achieve this I would be fascinated." ... you mean, like a hair drier?

@hamena314 I believe our device does not even contain fans, although it does get hot and is designed for use in a fairly hot environment.

@Bomskie: From the question I am unsure, if the protective case is air-tight or not, I've asked this in the comments. If it is air-tight, how does it get right of the produced heat from the CPU / GPU?

@JozefWoods I doubt this device has a GPU, the CPU will be some crappy microprocessor. We are not talking about a server, laptop or desktop here, more of an embedded device. Like a "smart" electric meter.

@hamena314 Hard to attach, lots of noise etc... The attack we witnessed was with a fairly small box, internal battery etc... Perhaps some LED lightbulbs? The device is not airtight as there are gaps in plastic, but very small. Probably airholes around back, but attack was to front of device.

"The attack we witnessed..." - your question describes a theoretically sounding attack on a theoretical device. If you have witnessed an attack to a real, physical device, please update your answer and include as much information as you can. Else the question will be too broad I think.

@hamena314 We saw another product (not ours) get attacked by someone installing a cube like box to the front of it, which stopped it working. We want to know if this could be done with a wave, or heat as suggested above. Any device I/we make in future will most likely be vulnerable to this, so we want to ensure it's something we can defend/detect against.

@k1308517 What I heard from a colleague of mine is that for example an Raspberry PI shutsdown after you make a photo with light. Maybe you can exploit this with the airholes?

@Bomskie True, but would this affect all devices? Furthermore, getting the flash inside would be difficult due to casing.

@k1308517 You have not specified how big those holes are but let's say the holes are 2mm and placed in a round pattern. It will depend on the size of the case and wether the case is solid black or not (black cases will absorb the light). But I think with the right flash through those holes you can easily light up that case from the inside. But still as has been stated before, we are all willing to help you but we do not have enough information for an desicive answer.

@Bomskie Sorry for being vague. Getting access to holes would be hard as they are around back, but as case is white plastic getting light through the case would probably be possible? However, this device is not a raspberrypie, think of it like a smart meter for electric consumption monitoring.

@k1308517 Allright maybe you can give this a read and see why the raspberry crashes. Maybe this will help you evaluate wether it applies to your case too Xenon Death Flash: a free physics lesson

@Bomskie Still a good idea, but sadly only works on Pi. Someone earlier mentioned using a laser, since the plastic is white and thin that might be worth researching. Hopefully I won't end up melting the plastic though, or could at least somehow put some type of protection first?