Yes, all cloud backup and storage services are potentially susceptible to cyber-attacks and this means that any data stored upon the cloud could also be compromised as a result of such attacks! With this danger in mind, and as was discussed earlier on in this guide, it is highly recommended to choose a cloud backup provider offering secure, zero-knowledge encryption which encompasses all data backed-up to the cloud. By encrypting all backed-up data by default, this approach remains one of the best methods for ensuring all personal data will remain private and secure at all times whilst making use any cloud backup services.