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Re: Microsoft win2003server phone home


From: Valdis.Kletnieks () vt edu
Date: Mon, 04 Aug 2003 17:13:00 -0400

On Mon, 04 Aug 2003 10:37:20 -1000, Jason Coombs said:
Closing down *most* of these exposures is why the 'rpm' package manager
supports using PGP to sign the packages...

You *do* realize that digital signatures can be forged with theft of private
keys, right?

Yep, fully aware of that.  On the other hand, there's the *presumption* that
the machine that RedHat or Sendmail do the signing on is somewhat more hardened
than the externally-visible server that the files live on.

I was also aware of all the other points you brought up - which is why I said "*most*
of the holes" - the note was getting quite long enough already. (As it was, I axed a
mention of the Verisign/Microsoft cert whoops due to length - if I hadn't scared the OP
off the concept of automated updates already, adding more to the list wouldn't change
matters).

On the flip side, *most* of the interesting MITM attacks on code update require the
attacker to wait for the target to do an update.  For the *vast* majority of systems
on the Internet, the benefit of having recently patched code or AV-scanner signatures
*far* outweighs the risks of actually being targeted during an update.  There is, indeed,
no absolute security - it's all about minimizing *total* risk.

Remember - you're downloading the update (code or AV) to fix a *known* exposure.
How bad a burn would Mimail have had if people *didnt* have automated AV updates?
How much less of a burn would CodeRed or Nimda have had if more people had
visited WindowsUpdate on a regular basis?

It's the same issue as vaccinating children against diseases - yes, some very small
percentage of children do have nasty side effects from the various vaccines.  But
that needs to be balanced against the dangers of not being vaccinated at all....

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