In the context of forensic acquisition of a compromised Azure VM, it is crucial to maintain the integrity of the evidence. The backup copy of the snapshot should be taken before any operations that could potentially alter the data are performed. This means creating the backup copy in a blob container as a page blob before mounting the snapshot onto the forensic workstation.

Here’s the process:

Create Snapshot: First, a snapshot of the VM’s disk is created to capture the state of the VM at the point of compromise.

Backup Copy: Before the snapshot is mounted onto the forensic workstation for analysis, a backup copy of the snapshot should be taken and stored in a blob container as a page blob.

Maintain Integrity: This step ensures that the original snapshot remains unaltered and can be used as evidence, maintaining the chain of custody.

Forensic Analysis: After the backup copy is secured, the snapshot can be mounted onto the forensic workstation for detailed analysis.

Documentation: All steps taken during the forensic acquisition process should be thoroughly documented for legal and compliance purposes.

References:

Microsoft’s guidelines on the computer forensics chain of custody in Azure, which include the process of handling VM snapshots for forensic purposes1.