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PHP Resource Exhaustion Denial of Service
From: full-disclosure () lists netsys com (Kurt Seifried)
Date: Wed, 24 Jul 2002 00:57:56 -0600

Perhaps you could put this on a site that is available? I have had no luck
accessing  http://www.murphy.101main.net/php-apache.c. Alternatively if you
could email it to me I would appreciate it.

Kurt Seifried, kurt () seifried org
A15B BEE5 B391 B9AD B0EF
AEB0 AD63 0B4E AD56 E574
http://seifried.org/security/


----- Original Message -----
From: "Matthew Murphy" <mattmurphy () kc rr com>
To: "BugTraq" <bugtraq () securityfocus com>; "SecurITeam News"
<news () securiteam com>; "Full Disclosure" <full-disclosure () lists netsys com>
Sent: Saturday, July 20, 2002 7:45 PM
Subject: [Full-disclosure] PHP Resource Exhaustion Denial of Service


The PHP interpreter is a heavy-duty CGI EXE (or SAPI module, depending on
configuration) that implements an HTML-embedded script language.  A
vulnerability in PHP can be used to cause a denial of service in some
cases.

PHP's install process on Apache requires a "/php/" alias to be created, as
it resolves CGI paths to a virtual.  (e.g, /php/php.exe not
C:\php\php.exe).

To solve the obvious security vulnerability posed by allowing PHP to run
from the web, the development team added a cgi.force_redirect option that
is
enabled by default in Apache.

However, regardless of the force_redirect value, it is still possible to
load the binary without a script path:

(e.g, http://localhost/php/php)

A problem exists in PHP; specifically, it does not terminate when given no
command-line arguments.  A consistent flow of requests like the above will
exhaust all resources for CGI/ASAPI on the server.

Exploit: http://www.murphy.101main.net/php-apache.c

I tried to make sure this would run on Linux/BSD, but no guarantees...
Compiles cleanly on WinMe with MSVC 6.0.

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