Hi desgnr,
Assuming you are talking about Ransomware (http://usa.kaspersky.com/internet-security-center/threats/ransomeware), the outcome of an infection is an ENcrypted file system and as long as your cloud provider does supports versioning, all files can be made accessible again: Simply revert them to a state where the Ransomware did not encrypt them yet.
Kind regards,
Florian
