Re: Disturbing news..

Jesse Pollard
2001-03-28T15:52:42Z

Russell King <rmk@arm.linux.org.uk>
>
> On Wed, Mar 28, 2001 at 08:40:42AM -0600, Jesse Pollard wrote:
> > Now, if ELF were to be modified, I'd just add a segment checksum
> > for each segment, then put the checksum in the ELF header as well as
> > in the/a segment header just to make things harder. At exec time a checksum
> > verify could (expensive) be done on each segment. A reduced level could be
> > done only on the data segment or text segment. This would at least force
> > the virus to completly read the file to regenerate the checksum.
>
> Checksums don't help that much - virus writers would treat it as "part
> of the set of alterations that need to be made" and then the checksum
> becomes zero protection.
>
[ snip of good stuff ]
> Therefore, if you follow good easy system administration techniques, then
> you end up minimising the risk of getting:
>
> 1. viruses
> 2. trojans
> 3. malicious users
>
> cracking your system. If you don't follow these techniques, then you're
> asking for lots of trouble, and no amount of checksumming/signing/etc
> will ever save you.

Absolutely true. The only help the checksumming etc stuff is good for is
detecting the fact afterward by external comparison.

I like MLS for the ability to catch ATTEMPTS to make unauthorized
modification.

-------------------------------------------------------------------------
Jesse I Pollard, II
Email: pollard@navo.hpc.mil

Any opinions expressed are solely my own.