Infrared Brute Force Attack Unlocks TiVo

While the era of the TiVo (and frankly, the idea of recording TV broadcasts) has largely come to a close, there are still dedicated users out there who aren’t quite ready to give up on the world’s best known digital video recorder. One such TiVo fanatic is [Gavan McGregor], who recently tried to put a TiVo Series 3 recorder into service, only to find the device was stuck in the family-friendly “KidZone” mode.

Without the code to get it out of this mode, and with TiVo dropping support for this particular recorder years ago, he had to hack his way back into this beloved recorder on his own. The process was made easier by the simplistic nature of the passcode system, which only uses four digits and apparently doesn’t impose any kind of penalty for incorrect entries. With only 10,000 possible combinations for the code and nothing to stop him from trying each one of them in sequence, [Gavan] just needed a way to bang them out.

After doing some research on the TiVo remote control protocol, he came up with some code for the Arduino using the IRLib2 library that would brute force the KidZone passcode by sending the appropriate infrared codes for each digit. He fiddled around with the timing and the delay between sending each digit, and found that the most reliable speed would allow his device to run through all 10,000 combinations in around 12 hours.

The key thing to remember here is that [Gavan] didn’t actually care what the passcode was, he just needed it to be entered correctly to get the TiVo out of the KidZone mode. So he selected the “Exit KidZone” option on the TiVo’s menu, placed his Arduino a few inches away from the DVR, and walked away. When he came back the next day, the TiVo was back into its normal mode. If you actually wanted to recover the code, the easiest way (ironically) would be to record the TV as the gadget works its way through all the possible digits.

Back in 2004, there were so many TiVo hacks hitting the front page of Hackaday that we actually gave them a dedicated subdomain. But by the end of 2007, we were asking what hackers would do with the increasingly discarded Linux-powered devices. That people are still hacking on these gadgets over a decade later is truly a testament to how dedicated the TiVo fanbase really is.

[Thanks to Chris for the tip.]