June 17, 2008
It is sometimes also called Hidden Protected Area and it is an area of your hard disk which is normally not visible for the operating system and therefore the applications. It was first introduced in the ATA-4 standard and is defined in ATA-5 as optional feature which is supported by most modern hard disks. The normal use case of this is for system recovery and the backup of important configuration data.
So why is this security relevant? For law enforcement agencies and forensic experts it is important to detect HPAs and recovery data from it. For one someone could hide some sensitive data in it or there could be evidence or traces if the owner does not know about the HPA.
But it is also important for any business and home user, e.g. if you want to fully override your hard disk you need to make sure you also override the HPA. If you’re a user of a current Linux kernel you’re lucky – the kernel will deactivate (temporary) the HPA during booting and so can override everything without problems.
Here are some links which will help you do detect / remove the HPA from your hard disk:
- Computer Forensics and the ATA Interface
- Detecting Host Protected Areas (HPA) in Linux
- Removing Host Protected Areas (HPA) in Linux (disk_sreset Tool)
- HDAT2 (config tool for DOS, with many features)