Re: wpad.dat attack on Linux Apache server

From	Richard Kettlewell <rjk@greenend.org.uk>
Newsgroups	comp.os.linux.networking, comp.os.linux.security, comp.infosystems.www.servers.unix
Subject	Re: wpad.dat attack on Linux Apache server
Date	2013-05-24 17:38 +0100
Organization	Anjou
Message-ID	<87d2sgl4e2.fsf@araminta.anjou.terraraq.org.uk> (permalink)
References	(8 earlier) <mr-011092.14433624052013@News.Individual.NET> <519f6593$0$15954$e4fe514c@news2.news.xs4all.nl> <mr-D7D3D2.15141924052013@News.Individual.NET> <8761y8qxcr.fsf@araminta.anjou.terraraq.org.uk> <mr-870DFD.16265624052013@News.Individual.NET>

Cross-posted to 3 groups.

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Sandman <mr@sandman.net> writes:
> Richard Kettlewell <rjk@greenend.org.uk> wrote:

>>>> Because of your use of wildcard DNS *everyone* who starts their
>>>> webbrowser will find wpad.their.domain then look for it on your
>>>> webserver.
>>>
>>> Why? I mean - when they go to wpad.their.domain, why would they end
>>> up with the IP of my server, or the CNAME of cluster.mydomain.com
>>>
>>> That's the part I just can't understand.
>> 
>> Perhaps quoting some of the domain names involved would clarify
>> matters.
>
> Yeah, ok.
>
> So a client to me, for example http://www.stadsnat.se has their DNS set 
> up as such:
>
>> host www.stadsnat.se
> www.stadsnat.se is an alias for cluster.atlascms.se.
> cluster.atlascms.se has address 94.247.170.170
>
> Now, atlascms.se WAS a wildcard DNS, but isn't any longer.
>
> Even so, the requests I get look largely like this:
>
> 94.254.41.78 cluster.atlascms.se - [24/May/2013:16:25:24 +0200] "GET 
> /wpad.dat HTTP/1.1" 200 70 "-" "Mozilla/5.0 (compatible; MSIE 10.0; 
> Win32; Trident/6.0)"
>
> I.e. a request to that domain name, not to a wpad subdomain. So the 
> wildcard DNS thing doesn't seem to even apply... Or am I mistaken?

I agree; I think the wildcard was probably a red herring, and the longer
it gets since you removed it, the more certain that is (although it’s
worth remembering that not all DNS clients honor TTLs correctly).

The request doesn’t seem consistent with the way that wpad searching is
described as working, but of course it may be that there’s more to the
implementation that the various descriptions online imply.

Do you have any idea how many distinct addresses are involved?  Are they
in fact _all_ Swedish IP addresses or are any of them from further
afield?  Can you tell whether any are associated with any of your
customers (e.g. if you keep logs of where they upload from, do any of
the oddly behaving clients appear there)?

Have you recently annoyed anyone who might have sufficiently poor
judgement to launch a DDoS attack?

-- 
http://www.greenend.org.uk/rjk/

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Thread

wpad.dat attack on Linux Apache server Sandman <mr@sandman.net> - 2013-05-24 11:22 +0200
  Re: wpad.dat attack on Linux Apache server Richard Kettlewell <rjk@greenend.org.uk> - 2013-05-24 10:37 +0100
    Re: wpad.dat attack on Linux Apache server Sandman <mr@sandman.net> - 2013-05-24 11:44 +0200
      Re: wpad.dat attack on Linux Apache server Richard Kettlewell <rjk@greenend.org.uk> - 2013-05-24 11:04 +0100
        Re: wpad.dat attack on Linux Apache server Sandman <mr@sandman.net> - 2013-05-24 12:13 +0200
          Re: wpad.dat attack on Linux Apache server Richard Kettlewell <rjk@greenend.org.uk> - 2013-05-24 11:20 +0100
            Re: wpad.dat attack on Linux Apache server Sandman <mr@sandman.net> - 2013-05-24 12:23 +0200
              Re: wpad.dat attack on Linux Apache server J G Miller <miller@yoyo.ORG> - 2013-05-24 11:07 +0000
                Re: wpad.dat attack on Linux Apache server Sandman <mr@sandman.net> - 2013-05-24 14:43 +0200
                Re: wpad.dat attack on Linux Apache server Casper H.S. Dik <Casper.Dik@OrSPaMcle.COM> - 2013-05-24 13:05 +0000
                Re: wpad.dat attack on Linux Apache server Sandman <mr@sandman.net> - 2013-05-24 15:14 +0200
                Re: wpad.dat attack on Linux Apache server Joe Beanfish <joebeanfish@nospam.duh> - 2013-05-24 13:39 +0000
                Re: wpad.dat attack on Linux Apache server Sandman <mr@sandman.net> - 2013-05-24 16:23 +0200
                Re: wpad.dat attack on Linux Apache server Richard Kettlewell <rjk@greenend.org.uk> - 2013-05-24 15:13 +0100
                Re: wpad.dat attack on Linux Apache server Sandman <mr@sandman.net> - 2013-05-24 16:26 +0200
                Re: wpad.dat attack on Linux Apache server Richard Kettlewell <rjk@greenend.org.uk> - 2013-05-24 17:38 +0100
                Re: wpad.dat attack on Linux Apache server Sandman <mr@sandman.net> - 2013-05-24 19:02 +0200
                Re: wpad.dat attack on Linux Apache server Richard Kettlewell <rjk@greenend.org.uk> - 2013-05-24 18:45 +0100
                Re: wpad.dat attack on Linux Apache server Sandman <mr@sandman.net> - 2013-05-24 21:12 +0200
                Re: wpad.dat attack on Linux Apache server Casper H.S. Dik <Casper.Dik@OrSPaMcle.COM> - 2013-05-24 16:47 +0000
                Re: wpad.dat attack on Linux Apache server Sandman <mr@sandman.net> - 2013-05-24 18:53 +0200
                Re: wpad.dat attack on Linux Apache server J G Miller <miller@yoyo.ORG> - 2013-05-24 17:15 +0000
                Re: wpad.dat attack on Linux Apache server Sandman <mr@sandman.net> - 2013-05-24 21:20 +0200
                Re: wpad.dat attack on Linux Apache server Richard Kettlewell <rjk@greenend.org.uk> - 2013-05-25 08:45 +0100
                Re: wpad.dat attack on Linux Apache server Sandman <mr@sandman.net> - 2013-05-25 09:54 +0200
                Re: wpad.dat attack on Linux Apache server Sandman <mr@sandman.net> - 2013-05-25 10:04 +0200
                Re: wpad.dat attack on Linux Apache server Casper H.S. Dik <Casper.Dik@OrSPaMcle.COM> - 2013-05-26 10:12 +0000
                Re: wpad.dat attack on Linux Apache server "David W. Hodgins" <dwhodgins@nomail.afraid.org> - 2013-05-24 13:50 -0400
                Re: wpad.dat attack on Linux Apache server Richard Kettlewell <rjk@greenend.org.uk> - 2013-05-24 19:10 +0100
                Re: wpad.dat attack on Linux Apache server Richard Kettlewell <rjk@greenend.org.uk> - 2013-05-24 19:15 +0100
                Re: wpad.dat attack on Linux Apache server Sandman <mr@sandman.net> - 2013-05-24 21:33 +0200
                Re: wpad.dat attack on Linux Apache server Richard Kettlewell <rjk@greenend.org.uk> - 2013-05-25 08:38 +0100
                Re: wpad.dat attack on Linux Apache server Sandman <mr@sandman.net> - 2013-05-24 21:25 +0200
                Re: wpad.dat attack on Linux Apache server Whiskers <catwheezel@operamail.com> - 2013-05-25 15:52 +0100
                Re: wpad.dat attack on Linux Apache server Roger <invalid@invalid.invalid> - 2013-05-25 17:19 +0100
                Re: wpad.dat attack on Linux Apache server J G Miller <miller@yoyo.ORG> - 2013-05-25 17:22 +0000
                Re: wpad.dat attack on Linux Apache server Sandman <mr@sandman.net> - 2013-05-25 19:41 +0200
              Re: wpad.dat attack on Linux Apache server Chris Davies <chris-usenet@roaima.co.uk> - 2013-05-24 12:31 +0100
                Re: wpad.dat attack on Linux Apache server Sandman <mr@sandman.net> - 2013-05-24 14:29 +0200
                Re: wpad.dat attack on Linux Apache server Chris Davies <chris-usenet@roaima.co.uk> - 2013-05-24 23:45 +0100
  Re: wpad.dat attack on Linux Apache server Sandman <mr@sandman.net> - 2013-05-24 14:49 +0200

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