ASP vulnerability with Alternate Data Streams

[aleph1 () DFW NET (Aleph One)]

---------- Forwarded message ----------
Date: Tue, 30 Jun 1998 15:27:32 +0200
From: Paul Ashton <paul () ARGO DEMON CO UK>
To: NTBUGTRAQ () LISTSERV NTBUGTRAQ COM
Subject: ASP vulnerability with Alternate Data Streams

Following on from the last .asp vulnerability which applied to
URLs ending in spaces, and the previous that allowed .asps to
be read if they end in ".", it turns out that there is yet
another due to Alternate data streams.

The unnamed data stream is normally accessed using the filename
itself, with further named streams accessed as filename:stream.
However, the unnamed data stream can also be accessed using
filename::$DATA.

If you open http://somewhere/something.asp::$DATA it turns out
that you will be presented with the source of the ASP instead
of the output. Deja vu?!

It is left as an exercise for the reader to thing of further
implications in other programs running on NT. Obviously,
anything that to tries to restrict access based on filename
instead of ACLs is going to have a hard time after this and
the other recent revelations.

Paul