securely erasing internal SSD

[brijazz]

A friend (really, it WAS a friend!) recently fell for a scam wherein a popup appeared on their screen claiming to be from Apple and advised them call a phone number for assistance with an urgent issue with their Mac They did, and granted remote access to their system to whatever shady scammer was on the other end of the line. Eventually they figured out something was up and disconnected from the internet.

So now, I'm tasked with fixing this mess. If it was a spinning HD, I'd be fine... but they have an SSD as their boot drive, and I'm less familiar with security on SSDs. What's the best approach to securely zeroing everything when an SSD is involved (and how long might it take to perform the operation on a 256GB volume?

 

[Weaselboy]

You will find that the secure erase option is greyed out in Disk Utility on flash storage Macs so it cannot be done.

That said, there is no need to secure erase. A regular erase will kill anything that is on there.

https://support.apple.com/kb/PH14243

Just follow the steps at this link to erase the disk and reinstall the OS.

 

[mattysouthall]

In this instance i'd follow what @Weaselboy says. But if FileVault was enabled then erasing deletes the recovery key too so that is secure enough.

 

[Michael Anthony]

If you had full disk encryption (Filevault 2) then the data is scrambled anyway.

Some people say that you don't need to secure erase an SSD; I contest that since I've recovered deleted (not overwritten) files before with no trouble.

I'm only just starting to need to overwrite SSDs, which was possible in older versions of the OS and Disk Utility, I've been using a zero fill or 7 pass erase with a pre 10.11 version of OS X even if I have to remove the drive and wipe it that way over a USB connection.

There's also command line trickery to fill your drive with garbage data, and work case, you can make a disk image (not a sparse disk image) the size of the disk, and then securely erase the file (the terminal command for that is srm.)