[Xitami] Xitami DoS/DDoS (CFM, PHP, Perl, and *ALL* CGIs)...

[John Bradbury]

-----Original Message-----
From: xitami-admin@lists.xitami.org
[mailto:xitami-admin@lists.xitami.org]On Behalf Of Thomas J. Hruska
Sent: 29 April 2002 09:43
To: xitami@lists.xitami.org
Subject: Re: [Xitami] Xitami DoS/DDoS (CFM, PHP, Perl, and *ALL*
CGIs)...


At 04:06 PM 4/29/2002 +0200, Francis Turner writeth:
>Very interesting.
>
>I wonder if this explains my persisitant GSL/XML problem(s). Sounds 
>higly plausible.

Could you elaborate on those problems?  I have seen various, related
incidents in the past month or so since this issue arose.  The most recent
one is under Linux with CGIs causing the server to be very unresponsive
under heavy loads.  There was an earlier one with Win98 crashing on a low
memory system and many CGIs opening at once.  You get the idea...

>I suppose I'd better look at the source to fiure out how the XML/GSL 
>stuff differs from an external CGI. It is true that my XML problems have 
>got worse when I use statements like
>.xml from <filename>
>thus requiring more files to be opened at a given moment.

Remember that filters are CGIs in "disguise."  They have somewhat different
properties than CGIs, but are basically the same.

Also, unless you have 50-60 simultaneous users on the system using CGIs,
this problem will go unnoticed.  However, a malicious attacker can easily
cause a DoS/DDoS with a simple tool that just requests CGI-oriented scripts
on the remote server to be executed - the server is quickly brought to its
knees and other users are unable to get webpages (usually the browser
appears to hang when the server replies with zero bytes of data - a flaw in
one of the Windows API calls that the browser has little control over).

Hope this helps!


          Thomas J. Hruska -- shinelight@shininglightpro.com
Shining Light Productions -- "Meeting the needs of fellow programmers"
                  http://www.shininglightpro.com/

--
Xitami Users Mailing List -- For Xitami support
To unsubscribe: http://lists.xitami.org/mailman/listinfo/xitami