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the cyber heist

problem

image

(also, see pcapng file)

solution

The pcapng file is a Wireshark USB sniffer dump, obviously.

We see that there are four USB devices, each with their own address.

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In the device descriptor of each, we can see the manufacturer and product.

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There are four devices:

  • 1.1.0 is a high speed USB hub of some sort
  • 1.2.0 has an unknown product id but is made by holtek semiconductor, inc
  • 1.3.0 is a razer deathadder 2013 (mouse)
  • 1.4.0 is unknown all around, but is later revealed to be a drawing tablet

I know that whoever made this challenge definitely plays the game called osu!, where you need a tablet to be good.

We use the https://the-sz.com/products/usbid/ to lookup the idVendor of the unknown device and products and such.

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1.4.0 is a drawing tablet

At first I tried collecting mouse data that may spell out a flag with mouse motions, but I just got this instead:

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For a while, I was stumped, but then I saw this:

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Holtek semiconductor makes various office computer equipment, like keyboards and mice.

So, I pulled up the HID 1.11 spec here

I found some keyboard HID examples:

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and then did a google search for HID keycodes and found this list here I then decoded the flag using the HID data.

One helpful thing was finding this github thing on HID decoding tips

I used the usb.addr matches "^1.2" filter

I also added the HID data column

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Then, it was pretty easy to decode by hand