Vulnerability Note VU#440539

Digital Unix msgchk vulnerable to file contents disclosure via symlink redirection of profile

Overview

msgchk, a part of the MH mail system, reads the user's .mh_profile in order to obtain configuration options. If the .mh_profile is linked to another file with illegal format, the first line of that file will be displayed in an error message by msgchk.

I. Description

msgchk is the portion of the MH mail system that checks for new mail in the system spool folder. It reads the user's .mh_profile in order to obtain configuration options. If that file is linked to another file readable by the effective user of msgchk, and not of legal .mh_profile format, then msgchk will display the first line of that file in an error message.

II. Impact

If msgchk executes with the user's effective UID, there is no vulnerability here. If msgchk is protected to set another UID, there is a possibility that an attacker may view protected information.

III. Solution

The CERT/CC is currently unaware of a practical solution to this problem.

Remove setuid privileges from msgchk.

Systems Affected

Vendor	Status	Date Notified	Date Updated
DEC	Vulnerable	15-Nov-2001

References

http://www.securityfocus.com/bid/3320

Credit

This vulnerability was first described by Seung Huyn Seo.

This document was last modified by Tim Shimeall.

Other Information

Date Public:	2001-09-10
Date First Published:	2001-11-15
Date Last Updated:	2001-11-15
CERT Advisory:
CVE-ID(s):
NVD-ID(s):
US-CERT Technical Alerts:
Metric:	1.88
Document Revision:	11

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