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Re: [LUG] Linux - and security Part 2

 

On 08/11/12 11:01, Martijn Grooten wrote:
> 
> And /etc only to refer to just in case. Nothing on it would have been
> irreplaceable, it would just save me some time setting things up
> again. I don't think there was anything in /etc that I considered very
> important.

The point is /etc/shadow typically contains password hashes. With these
someone can guess your passwords to their hearts content.

Encrypting is about preventing disclosure, it is not the same thing as
backup. Some things you may not want to disclose, even if you can easily
recover or reset them. You probably knew your password, so didn't need
to recover it, but do you want someone else recovering it for you?

Similarly if you have sshd running to allow remote access, /etc/ssh will
contain the cryptographic material to impersonate your machine. Okay
probably not a major issue without /home, but wait where is the root
home directory (oops).

Sure these are not large threats to home users, but since when setting
up from scratch it is less effort to protect the whole disk(s) than to
protect /home, it is common sense to do the whole disk.

John is right that /var usage depends on what software is being used
(doesn't everything in computing depend on that?). Debian sticks
databases here by default for MySQL and Postgres, mail servers queue
email here, cron puts jobs here, amongst plenty of other things.

But whilst you might not do any of those things now, will you change the
encyption of / or /var when you decide to do so? Will you even know or
care if a particular application writes data there? Judging by the fact
I often choose not to add encryption to existing partitions or systems
the answer for most folk is probably "no". Like me once it works they'll
do the minimum in the expectation (probably correct) that they are less
likely to break any thing that way. Breaking encryption is of course
especially painful as data recovery is usually restricted to the
"restore from backup" option.

Again I risk recommending things I don't necessarily do routinely, but
when I do encrypt a partition I ALWAYS do the whole disk.

I know enough to know that I don't know enough detail about what goes
where on disk to safely leave bits exposed.

I've been doing it long enough to be confident that if I don't know,
plenty of other people won't know either.

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