OSEC

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Re: Positive Technologies Security Advisory 2003-0307: DoS-attack in Kerio WinRoute Firewall

From: Peter Pentchev (roamringlet.net)
Date: Tue Apr 01 2003 - 01:49:58 CST

On Mon, Mar 31, 2003 at 10:00:26AM +0400, Dmitry Maksimov wrote:
[snip]
> Positive Technologies reports that single simple HTTP request to Kerio
> Winroute Firewall Web administration interface (TCP/4080)
>
> GET / HTTP/1.0
> Authorization: Basic XXX
>
> instead of correct one:
>
> GET / HTTP/1.0
> Host: server
> Authorization: Basic XXX
>
>
> causes 100% CPU utilization of attacked computer.

Hmm. Correct me if I'm wrong, but IMHO version 1.0 of the HTTP protocol
does *not* require a Host header in the request. The Host header is a
requirement in HTTP/1.1 for virtual hosting, isn't it? Thus, an
HTTP/1.0 request without a Host header is perfectly valid, and expected.
This would mean that this application breaks not only on invalid
requests, but also on legitimate ones.

G'luck,
Peter

--
Peter Pentchev roamringlet.net roamsbnd.net roamFreeBSD.org
PGP key: http://people.FreeBSD.org/~roam/roam.key.asc
Key fingerprint FDBA FD79 C26F 3C51 C95E DF9E ED18 B68D 1619 4553
I am jealous of the first word in this sentence.

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