HP ink cartridge DRM bypass demonstrated using physical man-in-the-middle-attack

A refilled HP ink cartridge has been demonstrated using a man-in-the-middle attack to bypass HP’s strict printer ink digital rights management (DRM), which prevents consumers from using generic cartridges. YouTube creator Jay Summet shared a video (via Hackaday) showing this particular attack that lets users bypass HP’s user-unfriendly DRM practices.

Ink cartridge hacks have proliferated in the ink cartridge markets, especially as HP and other printer manufacturers sell their ink at exorbitant prices (presumably to recoup their initial investment in their printers) which they reportedly sell at a loss. Because of these high prices, many have resorted to using third-party cartridges, which printer makers have attempted to stop by embedding chips.

Printers now need to detect these embedded chips before recognizing the cartridges; so, third-party-ink makers resorted to refilling old cartridges to circumvent this security feature. The original ink cartridges then received page limiters that required end-users to replace the ink after printing a certain number of pages, even if the cartridge still had some ink left.

This is where the man-in-the-middle attack happens — the ink refiller added a flexible PCB on the cartridge’s original contacts and routed the signal to a chip. This then alters the original signal to tell the printer that it hasn’t reached its page limit, which is then rerouted to another set of contacts that overlay the original ones. Because of this, the printer thinks that it’s talking to an original, unaltered cartridge.

The chip hack is the latest attempt that third-party ink makers have made to assuage the negative experience consumers have with printers — particularly, HP-branded ones. The company is defending its move to limit third-party ink like these, claiming security issues, and has even made ads saying its printers are ‘made to be less hated’. However, the company’s anti-consumer moves, particularly in the printer space, are what’s driving them to buy generic cartridges. In fact, there are numerous lawsuits against printer DRM and the like. But as it takes time for cases like this to go through the legal system, users have to resort to creative solutions to keep their printers usable without having to pay through the nose for ink.