iOS tethering password can be cracked in under 1 minute, but it requires four very expensive graphics cards.
Anyone who has an iPhone or iPad has probably noticed the interesting passwords that iOS managed to generate for its tethering hotspots. It now appears that the collection of words consists of about 52,500 entries, and as true random generation is not possible where computers are concerned, it means that the words and numbers count must be cracked backwards to decipher the security generation algorithm. And that is precisely what happened.
Three German researchers from FAU (Friedrich-Alexander-Universität) acquired a WiFi connection created by iOS, and then they set an AMD Radeon HD 6990 GPU to work trying to crack it. After taking only 50 minutes to get in with brute force, the researchers subsequently realized that only a handful (1,842) of the short English words were actually being used, and were able to streamline a cracking algorithm for the process. Now using four AMD Radeon HD 7970 GPUs, they can crack a default generated password in a mere 50 seconds. The reasoning behind using a GPU is that, while CPUs have faster speeds over fewer cores, most GPUs have over 300 cores that allow incredibly parallel processing power for graphics and evidently brute force attacks as well.
Now before we start freaking out, let's just realize that most people don't walk around with $1,600 worth of graphics cards in their pockets, along with a 1,200 watt rated battery to power it all for long enough to coincidentally find an iOS tethering point and crack it. That being said, it does raise an important security issue of not only changing your default passwords, but also that commercially used password generation needs to step up its game with more complexity and length of its passwords. And, to be fair to Apple, at least it attempted a password generation technique, unlike some companies who have a single standard password all the time.