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From: FXJWK@ALASKA.BITNET (Jo Knox - UAF Academic Computing)
Newsgroups: comp.virus
Subject: Re: protecting mac files via locking (Mac)
Message-ID: <0003.9106261903.AA01188@ubu.cert.sei.cmu.edu>
Date: 25 Jun 91 19:56:52 GMT
Sender: Virus Discussion List <VIRUS-L@LEHIIBM1>
Lines: 29
Approved: krvw@sei.cmu.edu

On 21 Jun 91, mike@pyrite.SOM.CWRU.Edu (Michael Kerner) says:

> NO!  ABSOLUTELY NOT TRUE IN ANY WAY, SHAPE, OR FORM.  IT IS IMPOSSIBLE TO
> PROTECT A FILE BY LOCKING IT.  PERIOD.  ABSOLUTELY NOT.  IT DOESN'T HAPPEN.

Agreed.

> The only way to protect a file is to have it on a locked volume.

Depends upon how the volume is locked; the only true locking is hardware
write protection, available on floppies and some optical drives (I think).

> However, I have an "utility" which will
> overwrite any resource in any file, and that's all the more specific I am
> going to get about it because I don't want some amateur hack reading this
> to get any ideas.  Saying that it can be done is bad enough - it encourages
> the ones that don't know ... yet.  At any rate, file locking AND PROTECTING
> (via some sector editor) do not stop this "utility" from working - no, it's
> not ResEdit, but I haven't tried ResEdit, although I would assume that it
> won't work.

I don't think any hacker's going to be surprised at this information;
"File Locked", "File Busy", "File Protect" are just bits in the header
information of the file; there are lots of utilities which can modify
some or all of these file attribute bits---if Finder (just another
program to the Mac) can set these bits, it's evident that other
programs can, too, such as ResEdit, MacTools/ FileEdit, SUM Tools,
Fedit Plus, and DiskTop DA, to name just a few.
jo