mailing list archives
Re: Re: E-Mail viruses
From: Valdis.Kletnieks () vt edu
Date: Mon, 08 Mar 2004 02:18:56 -0500
On Sat, 06 Mar 2004 01:47:13 +0100, starwars said:
For security reasons, the upgrade installer has been renamed to update.eex
and cannot be executed directly. [insert "this tremendously elegant
solution keeps you safe from viruses, because..." here].
On Sat, 06 Mar 2004 17:54:55 +1300, Nick FitzGerald <nick () virus-l demon co uk> said:
Yes, but to get through to Kurt's users, the malware (or its sender)
has to guess (or know if it is a directed or insider attack, in which
case "protection" is fundamentally harder anyway) the "right"
extension. Limiting ourselves to three-character-only, non-case
sensitive ASCII alphanumerics, that is a one in 3^36 chance. Anything
else will be stopped as "unwanted", so a virus trying to "fake out"
this approach still won't get to the users behind a perimeter
filtering mechanism enforcing this kind of policy...
It's not 3^36, which is multiple billions, it's only 36^3, which is 46,656.
And only one has to get through to an idiot.
Anybody else got a mail server that blocked more than that many Netsky's
this weekend alone? Draw the obvious conclusion here...
And *that* was why I was dubious as to the real usefulness...