Secure Memory on Mac OS X

September 8, 2008 - Reading time: 2 minutes

Nothing cheeses me off more than lazy Mac OS X users who don’t lift a finger to secure their OS. Yeah, Macs are currently not the most common target for hacks and viruses (viri?), but that hardly means that they’re invulnerable.

You can read more about some OS X security stuff, but here’s the quickie way to turn on your secure virtual memory:

1. Open System Preferences.
2. Double-click the Security icon from within the Personal section.
3. Press on the padlock to enable changes.
4. Supply a username and permission possessing administrator rights.
5. Check the box for Use Secure Virtual Memory.

Even if this makes no sense to you, you should do it. If you don’t, talented hackers can read your swap files and gain access to all kinds of sensitive information… verily, they could read ANYTHING that gets stored in memory. Passwords, your web site logins, your porn…

A swap file is simply a temporary file that’s used while you edit a file. If you’ve ever used the OS X terminal, you may have edited files using one of the command line editors, like vi. You may have noticed that when you edit some_document.txt, there will be a file created some_document.txt.swp while you are editing the file… that file persists until you’re all done editing the file and you’ve closed the editor. Virtual memory works similarly… it writes the contents of the RAM to a temporary file. Enabling “Secure” virtual memory encrypts this temporary file while it’s on disk… so even if someone has access to your disk, they won’t be able to see the contents of your memory.

-- Everett Griffiths