Re: CRv2 - Questions

["Nick FitzGerald" <nick () virus-l demon co uk>]

"The Death" <thedeadh () netvision net il> wrote:

> 1) Is it known if the CRv2 worm will function like CRv1, in the matter of
> c:\noworm ? If so, then systems who were once infected (with the CRv1 worm)
> will actually not go trough step 7 (attacking www.whitehouse.gov)

"CRv2" *is* identical to "CRv1" except in that it has an effective 
random network address generator and it does not intercept page 
serving and return "defaced" pages.  (And note that the defaced page 
serving, like everything else in this worm, is done entirely from 
running code.  I've seen many well-meaning descriptions of cleaning 
it up that end with something to the effect of "search for and 
replace any defaced web pages" -- well, that's a waste of time if the 
only thing that could have "defaced" your server was Code Red, 
because there are no defaced web page files.)

> 2) Is it known for the destenation of attack used by the CRv2 worm? Is it
> still trying to attack the blocked IP as CRv1 ?

"CRv2" is identical to "CRv1" except...

It "attacks" the same IP in the same way at the same time for the 
same duration.

> 3) What, do you think, caused the 'black hat' who made CRv1 to release CRv2?

Do you know it was the same person?  Perhaps you should be talking to 
the authorities...

> It isn't too smart to send CRv1 to "check the ground", as CRv1 brought alot
> of awareness to the bug exploited, therefore CRv2 will have much less hosts
> to exploit. Might it be that the 'black-hat' was not aware of the short
> period of the PRNG he designed?

The evidence is that "CRv1" did *not* significantly reduce the
potential host-base for this exploit.  It was CRv2 that "took off" on
(US) Thursday.  If you think about the way CRv1 works, with every 
instance trying to hit the same sequence of machines, CRv1 *must* 
spread slowly because the first machine hit will "lead the pack" with 
all its offspring simply following in its footsteps.  Unless one of 
its early hits is a much more powerful machine or has much more 
bandwidth to exploit, the first victim will lead the way and the 
others will just keep following.  If that initial victim is stopped 
for whatever reason ("unexplainable" performance degradation causing 
a frustrated (and largely clueless) admin to reboot it being the most 
likely cause), the instance most closely at that first victims heels 
will take over the lead, with a growing pack following it.  It was 
this observation and the sudden explosive growth of Code Red on 
Thursday that tipped various people off that something new was 
happening.  You should check Stuart Sandiford's modelling of various 
Code Red attack reports (posted to incidents.org and the incidents 
list on Friday) to get more of an idea of these issues.


-- 
Nick FitzGerald
Computer Virus Consulting Ltd.
Ph/FAX: +64 3 3529854

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