full-disclosure - Re: Apache Killer

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Message-ID: <CALCvwp7kW+x902JghE1XhZ6VwSHk+CmXPCdeeYEQk-dT23G=8g@mail.gmail.com>
Date: Thu, 25 Aug 2011 06:25:51 +1000
From: "-= Glowing Sex =-" <doomxd@...il.com>
To: Davide Guerri <davide.guerri@...il.com>
Cc: full-disclosure@...ts.grok.org.uk
Subject: Re: Apache Killer

oops, did it again... forgot to cc the list :s


On 25 August 2011 06:25, -= Glowing Sex =- <doomxd@...il.com> wrote:

> Very nice stuff!
> I think kcope did grab the idea from something you actually mentioned once
> davide, lol,a reference to a website i think and mentioning the byte range.
> I played abit with this, changed the request of 0- to more like this,
>
> root@...ked:~# perl killapache.pl www.***.com
> IO::Socket::INET=GLOB(0x22016f8) HEAD / HTTP/1.1
> Host: www.***.com
> Range:bytes=0-
> Accept-Encoding: gzip
> Connection: close
> ^C
>
> This, when i added the If-Range was less successful so i removed that, and
> changed the 0- section to one wich includes -doc_size , this produced a
> difference... and oh, i did also make it print "$sock $p"; for alittle to
> watch the header sending... alot of time it was not adding on the $p , it
> stopped at 0-.
> Interesting anyhow to play with the advisory/opatch and exploit.. it
> produces some wicked results on many httpds. I mean instant death to nearly
> all of freebsd v8 wich i have seen now...
> Anyhow, i hope we dont see another one lke this, i really blame apache for
> this, and wont ever hold an exploit coder to things wich are readable on
> some pages of apache, and just do not get brought to the fore, it is
> expected that everyone know how to update to dev, wich unfortunately is not
> goin to happen :P.
> anyhow, cheers for all the input on this, the patches for it work, and it
> is much nicer without any apache d0s :)
> thx, cheers,
> xd
>
>
>
>
> On 25 August 2011 00:26, Davide Guerri <davide.guerri@...il.com> wrote:
>
>> Hi Douglas,
>> I'd put optional spaces (\s*) between bytes= and the ranges and between
>> ranges.
>>
>> The following
>>
>> > bytes=    0-1,  5-69,-69
>>
>> is a valid Range header value (I mean that is accepted by apache).
>>
>> I agree with you about not to check the http method (GET/HEAD/POST seem to
>> be all vulnerable) and about the use of the [N]o[S]ub and the [L]ast flag.
>>
>> To sum up I'd rather use something like the following:
>>
>> > RewriteEngine On
>> > RewriteCond %{HTTP:Range} ([0-9]*-[0-9]*)(\s*,\s*[0-9]*-[0-9]*)+
>> > RewriteRule .* - [NS,L,F]
>>
>> I can say nothing about the efficiency of the Cond.
>>
>> If you remove any check that matches a single range webdav should work. It
>> seems really unusual for a service to use multiple ranges to me...
>>
>> Davide.
>>
>>
>>
>> On 24/ago/2011, at 15:40, Douglas Huff wrote:
>>
>> > I think this is a more complete rule that should be slightly more
>> efficient and thorough even though it's 3 separate matches:
>> >
>> > RewriteEngine On
>> > RewriteCond %{HTTP:Range} bytes=0-[0-9]+, [NC,OR]
>> > RewriteCond %{HTTP:Range} bytes=([0-9-],){4,} [NC,OR]
>> > RewriteCond %{HTTP:Range} bytes=[0-9,-]+,0-(,|$) [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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>> _______________________________________________
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>
>

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