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CERT Coordination Center

BSCW vulnerable to arbitrary file overwriting via symlink redirection of temporary file

Vulnerability Note VU#465971

Original Release Date: 2001-11-15 | Last Revised: 2001-11-15

Overview

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.

Description

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.

Impact

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.

Solution

Apply vendor patches; see the Systems Affected section below.

Vendor Information

465971
 
Affected   Unknown   Unaffected

BSCW.gmd

Notified:  July 16, 2001 Updated:  October 01, 2001

Status

  Vulnerable

Vendor Statement

http://bscw.gmd.de/Bulletins/BSCW-SB-2001-08.extract.txt

Vendor Information

The vendor has not provided us with any further information regarding this vulnerability.

Addendum

The CERT/CC has no additional comments at this time.

If you have feedback, comments, or additional information about this vulnerability, please send us email.


CVSS Metrics

Group Score Vector
Base N/A N/A
Temporal N/A N/A
Environmental N/A

References

Acknowledgements

This vulnerability was first described on the Bugtraq mailing list.

This document was last modified by Tim Shimeall.

Other Information

CVE IDs: None
Severity Metric: 4.73
Date Public: 2001-08-24
Date First Published: 2001-11-15
Date Last Updated: 2001-11-15 16:42 UTC
Document Revision: 14

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