Archive for May, 2008

SECURITY ALERT: Mac OS X 10.5.2 subverts FileVault

Saturday, May 10th, 2008

I apologize for not posting this earlier. I’ve been extremely busy lately, and I had discussed the issue with someone who said that he or she (he) was going to post about it (but hasn’t).

The security alert is for FileVault users running Mac OS X 10.5.2. You thought that FileVault encrypted your personal data, right? Wrong! In Mac OS X 10.5.2, the location of the CFNetwork caches was moved from ~/Library/Caches, which is within your home directory and thus encrypted, to /private/var/folders, which is not within your home directory and thus not encrypted. This means that anyone with physical access to your hard drive could, for example, determine which URLs you’ve loaded, even if your computer is shut down.

Note that nothing about this change was mentioned in the Mac OS X 10.5.2 release notes.

For further reference on this issue, see the thread that began in the WebKit SDK mailing list and was moved by me to the Macintosh Network Programming mailing list. Thanks to Eric Long, who noticed the change in the first place, and Ron Hunsinger, who performed testing that I was too lazy to do. (In my defense, I haven’t yet migrated my FileVault account from Tiger to Leopard, so the issue doesn’t affect me directly.)