mailing list archives
PHP Resource Exhaustion Denial of Service
From: full-disclosure () lists netsys com (Matthew Murphy)
Date: Sat, 20 Jul 2002 20:45:17 -0500
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:
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.
I tried to make sure this would run on Linux/BSD, but no guarantees...
Compiles cleanly on WinMe with MSVC 6.0.
- PHP Resource Exhaustion Denial of Service Matthew Murphy (Jul 21)