It depends on the service. The problem with these types of attacks is that overwrite the existing file. It's like modifying a word document and then saving it. Lots of cloud backup services that don't support versioning will overwrite all the old backup files. So it really depends on what cloud backup service you use. As Bert mentioned, I know our partner, iDrive, does maintain versions of previous files so you're covered.
I'll let someone who uses AC Backup comment on AC's versioning capability.
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