A VMDK, or VMware Virtual Machine Disk, is a file format that stores the contents of a virtual machine’s hard drive. It can hold operating system files, applications, user data, partition layouts, and metadata that let VMware platforms present the disk to a guest system as if it were a physical drive.
VMDKs matter in cyber security because they are portable containers for large amounts of sensitive data. Attackers may copy VMDK files during intrusion, steal them from backups or storage systems, or alter them to plant persistence and malware in a virtual environment. Defenders use the same format for legitimate purposes such as backups, incident response, cloning, and offline forensic analysis. Security teams should treat VMDKs as high-value assets: control access, encrypt storage, verify integrity, and monitor exports or snapshots to reduce the risk of data theft and unauthorized tampering.