Full Disclosure: Re: Apache Killer

[Davide Guerri <davide.guerri () gmail com>]

Hi Douglas,
I'd put optional spaces (\s*) between bytes= and the ranges and between ranges.

The following

> bytes=    0-1,  5-69,-69
is a valid Range header value (I mean that is accepted by apache).

I agree with you about not to check the http method (GET/HEAD/POST seem to be all vulnerable) and about the use of the 
[N]o[S]ub and the [L]ast flag.

To sum up I'd rather use something like the following:

> RewriteEngine On
> RewriteCond %{HTTP:Range} ([0-9]*-[0-9]*)(\s*,\s*[0-9]*-[0-9]*)+
> RewriteRule .* - [NS,L,F]
I can say nothing about the efficiency of the Cond.

If you remove any check that matches a single range webdav should work. It seems really unusual for a service to use 
multiple ranges to me...

Davide.



On 24/ago/2011, at 15:40, Douglas Huff wrote:

> I think this is a more complete rule that should be slightly more efficient and thorough even though it's 3 separate 
> matches:
>
> RewriteEngine On
> RewriteCond %{HTTP:Range} bytes=0-[0-9]+, [NC,OR]
> RewriteCond %{HTTP:Range} bytes=([0-9-],){4,} [NC,OR]
> RewriteCond %{HTTP:Range} bytes=[0-9,-]+,0-(,|$) [NC]
> RewriteRule .? http://%{SERVER_NAME}/ [NS,L,F]
>
> I cannot remember if the second RewriteCond's syntax is supported by mod_rewrite and don't have a machine handy right 
> this moment to test effectiveness anyhow.
>
> This should stop any requests with a range starting with 0- specified as a range (first and third rule) or 4 or more 
> ranges included (second rule).
>
> -- 
> Douglas Huff
>
> On Aug 24, 2011, at 5:29 AM, Carlos Alberto Lopez Perez wrote:
>
> > On 20/08/11 14:05, Moritz Naumann wrote:
> > > On 20.08.2011 00:23 HI-TECH . wrote:
> > > > (see attachment)
> > > > /Kingcope
> > > Works (too) well here. Are there any workarounds other than rate
> > > limiting or detecting + dropping the traffic IPS-wise?
> > >
> > > Moritz
> > You can use the following redirect as a temporally workaround:
> >
> > # a2enmod rewrite
> >
> > RewriteEngine On
> > RewriteCond %{HTTP:Range} bytes=0-.* [NC]
> > RewriteRule .? http://%{SERVER_NAME}/ [R=302,L]
> >
> >
> >
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_______________________________________________
Full-Disclosure - We believe in it.
Charter: http://lists.grok.org.uk/full-disclosure-charter.html
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