BSCW is a groupware system that runs on a web server. BSCW follows symbolic links in tar files that it extracts into a user's local area. Accessing those links may allow the user to view arbitrary files viewable by the web server, and to overwrite files writable by the web server.
BSCW provides for a number of upload and download options, plus on-line access to documents via a "data bag" (a local area for each user). One of the features supported by BSCW is extraction of uploaded tar files into the "data bag." Reportedly, when a tar file containing symbolic links is extracted into the "data bag", BSCW will support access to the linked object under the web server's userid.
By creating symbolic links to files on the web server and placing them in a tar file, then extracting them into the "data bag," an attacker reportedly could view any file readable by the web server. By modifying these files via BSCW, the attacker may be able to overwrite files writable by the web server. Directly uploading symbolic
links will not work as the BSCW software either refuses this upload with an error message or hangs on the upload.
Apply vendor patches; see the Systems Affected section below.
This vulnerability was first described on the Bugtraq mailing list.
This document was last modified by Tim Shimeall.
|Date First Published:||2001-11-15|
|Date Last Updated:||2001-11-15 16:42 UTC|