Re: new codered worm penetrates content-filtering

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

Ryan Russell <ryan () securityfocus com> wrote:

> OK, I got a sample of one of the CodeReds from Chris Russel that had the
> "GET " in one packet, and the rest in subsequent packets.  They are whole
> IP packets, so it's not fragmentation.  The actual worm itself is simply
> CodeRed.b.  The only other weird thing I've noted is that the PSH flag is
> set on the first two packets from the attacker, after the handshake.  I
> don't think that's normal.

So, it's deliberate injection into the network in this psuedo- 
fragmented form, presumably to beat at least some IDSes or other 
filtering mechanisms.  If the rest of the code is unchanged, as you 
say, then any successfully exploited targets will then only be 
spreading the "normal" CodeRed.B, so it won't be too huge an 
outbreak.

People receiving these should consider how to approach the sending 
machine(s) because they are likely either friendly to hosting such 
dubious practises or compromised and unaware of this...


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

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