What is the most likely first step to recover from a denial-of-service attack where all hard disk data is lost?

The best initial step to recover from a denial-of-service attack that has resulted in the loss of all hard disk data is to contact the backup service. This is critical because, in the event of a data loss incident, access to backup data is essential for restoring lost files, configurations, and system states. Regular and reliable backups are a fundamental component of a robust disaster recovery strategy, ensuring that in moments of crisis, an organization can quickly restore its essential services with minimal disruption.

Relying on backups typically means that the most recent and important data can be recovered without facing more extensive recovery processes, which could be time-consuming or costly. Engaging with the backup service can provide immediate guidance on how to retrieve the backup data and restore operations effectively.

While there may be other options available, such as contacting a disk recovery service or rebuilding a RAID array, those steps may take longer and may not lead to a successful recovery of critical data, particularly if backups are in place and functioning properly. The focus should initially be on restoring what was lost from backups rather than attempting recovery from damaged hardware or other complex interventions.