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PHP local DoS: self-fetching throught HTTP


From: Ilya Teterin <alienhard () mail ru>
Date: 18 Jul 2001 13:29:01 -0000

PHP scripting allows "opening" files througth HTTP:

$file=fopen("http://host/page.html","r";);

If script opening itself throught HTTP, it will result in 
DoS attack:
as much as possible HTTP connections and great 
number of executing PHP scripts.
Timeout settings are useless.

Possible solutions:
- disable HTTP connections from local host
- limit number of connections from one host

Samlpe exploit: put "script.php" to 
www.freehosting.domain and make some HTTP 
request to it.

==begin of script.php==
<?php
$file=fopen "http://www.freehosting.domain/script.php";
,"r");
?>
===end of script.php===

Another way to use PHP script self-fetching is 
creating infinite-living scripts on server: before 
execution timeout exceed, script "opening" itself 
throught HTTP and continue its execution.

buggzy, Nerf Security Group
www.nerf.ru


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