It is almost a law of nature that any device with a chip and communication protocol can be hacked. This is true even for a projector with an HDMI port, for example. In addition to audio and video, hdmi also provides support for all kinds of metadata sending for digital rights management and protocols such as hdcp.
An irradiator is given as an example. If a person is presenting, he can infect his laptop by connecting it to the projector via HDMI. The next person who then connects to the projector with a company laptop is hacked by the projector, allowing an external person to hack into a company’s network. Electronics mechanic Kingkevin came up with something for it.
I2C is a serial communication bus designed by Philips nearly 40 years ago and also supported in HDMI. This legacy protocol is vulnerable to intrusion and requires at most an Arduino or Raspberry Pi. But in the case of Kingkevin, this standard is used to secure the HDMI connection with a firewall dongle. This only allows audio and video to pass through and blocks all other data.
The dongle is placed between the HDMI port of the device to be protected and the HDMI cable. One dongle is required per port, but it can also be transferred to another device once the dongle is set up.
The setup consists of copying the Extended Display Identification Data from the device for the toggle function to work. This is written in the rom of the dongle, which can be fixed by breaking a part of the printed circuit board. If the firewall is moved to another device, the write block must be removed by connecting the two contacts with a drop of solder. The EDID information for the new device can then be rewritten and soldered off.
Description, code and schematics of the sign are available for free on kingkevin’s own git website CuVoodoo, the dongle is available on Tindie for $8 but is currently out of stock.
Source: Tom’s Hardware
Source: Hardware Info
