Vulnerability Development mailing list archives

Re: How do web servers handle dropped connections?


From: H D Moore <hdm () SECUREAUSTIN COM>
Date: Fri, 25 Aug 2000 23:37:17 -0500

Walter Hop wrote:

Hi,

looking at the stars last night I was wondering: if I request a scripted
page /blah.pl from a webserver, the server starts the perl interpreter and
runs the script. What happens when the browser breaks the connection
with the web server before the script has finished? Is the script allowed
to execute fully and is the output being discarded afterwards, or is the
process killed immediately? In other words, can server side scripts be
aborted prematurely in this way - and for example corrupt open files or
leave inconsistencies in a database?


In my experience I noticed that scripts that are parsed by an external
command (perl) will continue execution even after the client has
disconnected.  Scripts that are interpreted by  server modules (php)
will stop execution as soon as the client disconnects.  The above
observations are with Apache 1.3.x servers only, I have no idea what
IIS/Netscrape/*Server does.

-HD

http://www.digitaldefense.net
http://www.digitaloffense.net


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