I have the exact same problem. The ubd process keeps popping up and I can't find a process killer in the App Store as they got rid of one called PKiller supposedly. Guess we have to wait for a jailbreak to be able to do these things..
It's weird how it's got something to do with iCloud but still runs even when my iCloud account is deleted. I'm pretty sure it's this process that draining my battery.
Just tried adding my iCloud account again and then deleted it- this stopped the ubd process and hasn't popped up for half an hour. Battery still drains relatively quick in proportion to my usage. 4% in 20 mins of not really doing anything intensive.. I think another running process must be secretly stealing my juice for its kids.
Gotta try and find another culprit..
I have the same problem you are having. Did you manage to figure out the source of the problem?
I can't seem to prevent the UBD process from increasing its process id and producing CPU spikes every 10 seconds. I've completely removed iCloud from my device and its still persistent in cycling.
Have tried deleting all apps that have ever stored documents and data and that doesnt work either. If I open passbook i noticed that ubd doesn't increment for a while. But it eventually starts again.
I've restored by device from new, added and remove icloud (so i could at least get my contacts on the phone).. nothing seems to prevent it..
Below is the only leads I could find on the problem..
https://discussions.apple.com/message/20364624#20364624 (Weird, this <-- link only brought up the reply i was talking about when signed out of apple discussions, by a user called msf01)
Message was edited by: Aidan Dwyer