From: pingouin at rhapsodyk.net (Simon Marechal)
Subject: interesting?

On Sat, Feb 01, 2003 at 01:54:36PM +0100, Simon Richter wrote:
> Hi,
> 
> > According to the analysis posted to NANOG by a number of
> > researchers (http://www.caida.org/analysis/security/sapphire/), 
> > It infected the majority of hosts within the first 10 minutes. 
> 
> [...]
> 
> > This seems important is because it shows that a high rate
> > of saturation can be achieved among network nodes as
> > effectively (if not more so) using random distribution, as by 
> > using a structured or hierarchical distribution strategy. 
> 
> Actually, that was what the worm author did. The algorithm generates new
> numbers from the current (i.e. it has some sort of knowledge what hosts
> have already been infected) plus a not-really-predictable component
> (system time, IIRC) plus some sort of counter because the system clock
> is so slow.
> 
> So what we have witnessed is the structured approach. The question
> remains whether the worm author is a maths wizard or just plain lucky.

Using a random distribution is easier to code than another kind. Plus,
if you use a hierarchical way, you'd better be a REALLY good math wizz
to make sure 2 worms won't cover the same ip-range.
Using a random distribution is the best no-brainer way to make sure
having 500 worms will produce a 500 times wider coverage.

PS:what you're describing looks like a pseudo random generator ... doesn't 
look like a structured approach. Do you have a link to that generator
description?

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