Russian firm ElcomSoft has discovered a new security flaw in iOS 10 backups. The new mechanism skips certain security checks, allowing us to try passwords approximately 2500 times faster compared to the old mechanism used in iOS 9 and older. This new vector of attack is specific to password-protected local backups produced by iOS 10 devices. The silver lining on the cloud is that this means any hacker wanting to exploit the weakness would have to target the computer you have made the backup onto, rather than trying to access the phone itself remotely.”]
Source: https://grahamcluley.com/upgrading-ios-10-backups-lot-faster-crack/