Best file shredding/Recovery

Question

Trying to make some files I had in a VM unrecoverable, I ran CCleaner in the VM and deleted everything I can from the inside, deleted the VM. And then I found out OneDrive had them, deleted it from there and off the PC again. Ran everything from my Recycle bin through bit defender shredder, recovered all my files through Recuva and did it again about twice.

I'm wondering if there was a free program I can use that will make everything non-recoverable. I want the most amount of "passes" I can get, I mind how long it takes. Unsure about the number of files that I have to delete but I'm not extremely worried about time.

What I would love to get your thoughts/help on is, what's a good file shredder I can use and a recovery system to test to see if any files are recovered. Thank you so much for your time and I hope you have a wonderful rest of your day! :)

Answer 1

What I used a while back was the open source Heidi Eraser program. (https://eraser.heidi.ie/) It does multiple passes on the selected volume with different shredding methods to choose from.

Complexity gets added when you have a VM in the mix. I wouldn't have bothered deleting files in the VM. If I were that concerned about the content, I'd have securely erased the image file you loaded into the VM to begin with.

If you have a standard VM setup you use, create a blank one without data as a master. When you want to work with sensitive data, spawn a copy of the master, load your data into it, and do what you want. When done, exit the VM and erase the working copy you made.

A bigger question for me is physical security. How might someone get to that sensitive data on your PC in the first place? How much trouble I would take to securely erase data would be a matter of how sensitive it was and how people might get to it.

I don't do a lot with VMs, but for data I'm really concerned about, it doesn't reside on the PC. It's stored on a USB thumb drive. When I'm not actively working with it, the thumb drive is unplugged and stored elsewhere.

Answer 2

CCleaner has this wipe free space or similarly called function in the advanced tab just for this case. Since it's proprietary software we don't know what exactly it does, but my guess would be that it overwrites the to-be-removed space with zeroes or random data probabling ignoring slack space. It's not as secure as the tools below.

If you were to boot up Linux tools like shred (mostly included in the distro) and srm (secure remove, usually need to install it first) (not 100% sure that they support the NTFS file system if you are using Windows). Or just use /dev/zero or /dev/random for overwriting the needed blocks. But since you already deleted the file, I am not sure how you would locate the needed blocks. Practically it would just be too much work.

Since NTFS file system has the so called slack space I would rather wipe the whole drive if that information is so critical. That's the only sure way to destroy any remaining data/metadata.

If I were you I would just boot up DBAN from dban.org and wipe the whole drive after making a backup. That's a sureway method and the software has multiple methods with selected amount of passes.

Then again if you are using a SSD you should instead download and use your manufacturer's secure erase software.