Reasonable setup

[0brand]

@goldstein-otg

If we’re talking about SSD,AFAIK no there is no easy way to securely delete Files on an SSD.

I wouldn’t trust anything to secure delete individual files on flash based storage. There is nothing that can reliably do that.

https://www.usenix.org/legacy/events/fast11/tech/full_papers/Wei.pdf

[pano]

Ok, and what about the case of wiping available space on a non-SSD HD, on the host, for the purpose of clearing previously saved VM states?

[tempest]

@pano

I understand that now, I am still not clear though about the advantage of immutable drives over always restoring the state to a particular snapshot.

there is essentially no difference. immutable drives automate that process. other drive states require you to do that manually.

I previously thought deletion of the temporary data is done when the machine is powered off, but as you mentioned (and as I’ve seen when I tested the immutable drives) it happens only at the next activation of the machine - so performing an active step after shutdown is required anyway.

if new data was immediately wiped after you shut down your virtual machine with immutable drives, you would never be able to update it.

For either of those cases - say we restored the machine to a previous state (for a normal drive), or just restarted it (in the case of an immutable drive) - doesn’t wiping available space help on the forensics front as well?

it might. depending on the type of drive, there may be some issues. but a wipe of your free space through one method or another is a tactic used.

Even in Tails, when working on ongoing projects one will need to save data somewhere, and clear it when it’s not necessary any more, so wiping issues still need to be handled.

disk wiping is an issue that involves a number of variables and generally involves a threat scenario where your computer or disk is obtained by an enemy. this is yet another example of where software alone is probably not enough.