Path: csiph.com!usenet.pasdenom.info!weretis.net!feeder4.news.weretis.net!news.musoftware.de!wum.musoftware.de!fu-berlin.de!uni-berlin.de!individual.net!not-for-mail
From: "Mel Smith" <med_cutout_syntel@aol.com>
Newsgroups: comp.lang.javascript
Subject: Thwarting DoS attacks
Date: Wed, 3 Oct 2012 09:41:17 -0600
Lines: 50
Message-ID: <ad34l0Fka06U1@mid.individual.net>
X-Trace: individual.net OgXum/u3gRSxvCkN3wTSsQa8RqJEPDNbbGqocPycZZMzYLoXng
Cancel-Lock: sha1:gBcQFyskN0eOHdTlbNs1t/oqa3c=
X-Priority: 3
X-MSMail-Priority: Normal
X-Newsreader: Microsoft Outlook Express 6.00.2900.5931
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.6157
X-RFC2646: Format=Flowed; Original
Xref: csiph.com comp.lang.javascript:16347

Hi:

   I have a download site for C/C++ programmers where they can download the
most current versions of our Harbour Language.

   For the past many months I have been undergoing DoS attacks whereby a 
person(s)
bypasses the 'manual' way of 'clicking' and downloading, and instead, 
automates this
process with a program to begin many downloads simultaneously to attempt to 
'drown'
my home office server (Apache 2.2.22). These downloads are aborted part way 
thru and
more downloads are started up.

   Of course, I can 'Deny' the IPs access, but this person just uses a 
different client proxy.

   I have approx 20 different anchors/links of the style below:

      <a  href="http://www.mysite.com/files/somefile.zip">Download Some 
File</a>

JAVASCRIPT:
   In the link statement above, and with javascript I regularly modify the 
'files' word in the
above statement to a different sub-directory at my site -- when loading is 
complete.

   However, my 'attacker' has again outsmarted me, and uses source 
investigation techniques
to determine the actual download sub-dir.

   Examining my Apache logs I see the vast stream of aborted downloads 
resulting in
'206' errors

Question:
   Is there a different download technique whereby my 'script'  (actually a 
C-based executable)
could intercept the download request, investigate it, then (perhaps) refuse 
the download request.

   As it is now, my script doesn't even know that this attack is happening.

Thanks for any Javascript guidance offered.

-Mel Smith