IOS – Is the message “You must change your passcode within 60 minutes” valid / non-malware

A few minutes ago, after unlocking my phone (iPhone 4, iOS 7.0.1) I got a dialog over the home screen:

Passcode Requirement

You must change your passcode within 60 minutes

and it offered to let me do so. I canceled. I've never seen this dialog before and I am worried it may be a sign of malware fishing for my passcode. Even on iOS 9.1, this dialog still happens:

There is very little on Google about this message, but what there is is:

• Someone else worried it may be malware, with no definitive answer (just "it can't be malware if it is not jailbroken", which is not true)
• Someone suggesting the passcode may be "too common" (IMO, unlikely for mine.)
• In both the above, a suggestion it may be related to a network profile, which I do not and never have had.

I changed my passcode manually, but am still worried about the source of the dialog and why it appeared. Is there a definitive answer?