Security Expert said that Cracking Tools like The GreyKey Can Unlock An iPhone In 6.5 Hours With A 4-Digit Passcode.

Last week, a Motherboard's report highlighted that GreyKey, a tool that allows law enforcement agencies to unlock up-to-date iPhones, th...

Last week, a Motherboard's report highlighted that GreyKey, a tool that allows law enforcement agencies to unlock up-to-date iPhones, the report didn't point out how much time is required to crack the iPhones. And now we have informed that a 6-digit passcode can be calculated in 11 hours.

This was revealed by John Hopkins Information Security Institute's Matthew Green, who said in his Tweet with an exploit that disables Apple's passcode-guessing protections, it would take 6.5 hours to unlock the iPhone with a 4-digit passcode, and 46 days to crack an iPhone with an 8-digit passcode.

Guide to iOS estimated passcode cracking times (assumes random decimal passcode + an exploit that breaks SEP throttling):
4 digits: ~13min worst (~6.5avg)
6 digits: ~22.2hrs worst (~11.1avg)
8 digits: ~92.5days worst (~46avg)
10 digits: ~9259days worst (~4629avg)

As Apple’s iOS security guide explains, There is an option that can erase an iPhone's data after 10 incorrect passcode guessing attempts and there are automatic delays after a wrong passcode has been entered more than five times. But apparently, GreyKey has found a way to avoid these delays and just keep guessing passcodes.

So we strongly recommend you that stop using the passcode only made by six numbers. Majority security experts have admitted that people should use an alphanumeric passcode that's at least 7 characters long and mixed with numbers, uppercase/lower letters, as well as symbols.

“People should use an alphanumeric passcode that isn't susceptible to a dictionary attack and that is at least 7 characters long and has a mix of at least uppercase letters, lowercase letters, and numbers,” Ryan Duff, a researcher who’s studied iOS and the Director of Cyber Solutions for Point3 Security, told me in an online chat. “Adding symbols is recommended and the more complicated and longer the passcode, the better.”

To change your device's passcode, go to Settings app on your Home screen, tap on Touch ID & Passcode, click on Change Passcode, select Custom Alphanumeric Code, and type your passwords. Do you have any comments on this?