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?
This message is the case when either:


Your device is enrolled under MDM and after deployment it will display something like image below.(https://www.apple.com/iphone/business/it/management.html)
Your passcode is too obvious and needs to be changed
Microsoft Exchange can force a passcode on your iPhone.




Obvious codes start with the following numbers: 


196* 
197*
198* 
199*
200*
201*


But also include:


1234
0000 (or any 4 same number combination)
0001 or 0010 or 0100 or 1000 (or any number with this pattern)
1379
2580
2468