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ESB-98.155 -- CERT Security Bulletin VB-98.10 -- Security Vulnerabilities in "mscreen" Serial Multiscreens utility (SCO)

Date: 14 October 1998

Click here for printable version
Click here for PGP verifiable version
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              AUSCERT External Security Bulletin Redistribution

                             
                ESB-98.155 -- CERT Security Bulletin VB-98.10
   Security Vulnerabilities in "mscreen" Serial Multiscreens utility (SCO)
                               14 October 1998

===========================================================================

The CERT Coordination Centre has released the following advisory concerning 
vulnerabilities dicovered in the SCO "mscreen" serial multiscreens utility.  
These vulnerabilities may allow local users to gain root privileged access.


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=============================================================================
CERT* Vendor-Initiated Bulletin VB-98.10
October 13, 1998

Topic: Security Vulnerabilities in "mscreen" Serial Multiscreens Utility
Source: SCO

To aid in the wide distribution of essential security information, the CERT
Coordination Center is forwarding the following information from SCO.
SCO urges you to act on this information as soon as possible. SCO contact
information is included in the forwarded text below; please contact them if
you have any questions or need further information.


=======================FORWARDED TEXT STARTS HERE============================

===========================================================================
SCO Security Bulletin 98.05
October 6, 1998
Security Vulnerabilities in "mscreen" Serial Multiscreens Utility
- - ---------------------------------------------------------------------------

I.   Description

Security vulnerabilities have been discovered in the SCO "mscreen"
serial multiscreens utility.

II.  Impact

The vulnerabilities could allow local users to gain root privileges.

An exploit script for one of the vulnerabilities has been published,
so we recommend that the patch described below be installed on all
affected systems as soon as possible.

III. Releases

This problem exists on the following releases of SCO operating systems:

     - SCO Open Desktop/Open Server 3.0 (all, also SCO UNIX 3.2v4)
     - SCO OpenServer 5.0 (all, also SCO Internet FastStart)
     - SCO CMW+ 3.0
	
Other SCO products are not affected.

IV.  Solution

For SCO CMW+, the mscreen utility is non-functional; however, a binary
is installed on the system with the set-user-id attribute.  This should
be disabled by executing the following command logged in as root:

	# chmod 0 /usr/bin/mscreen

For SCO OpenServer 5 and SCO Open Desktop/Open Server 3, SCO is providing
an interim patch to address this issue in the form of a System Security
Enhancement (SSE) package.

SSE016 contains new versions of the mscreen binary for each system type.
It is available for Internet download via anonymous ftp, and from the
SCOFORUM on Compuserve.

You can download the SSE package as follows:

Anonymous ftp (World Wide Web URL):

    ftp://ftp.sco.COM/SSE/sse016.ltr    (cover letter, ASCII text)
    ftp://ftp.sco.COM/SSE/sse016.tar.Z  (new binaries, compressed tar file)

Compuserve:

    GO SCOFORUM, and search Library 11 (SLS/SSE Files) for these filenames:

	SSE016.LTR	(cover letter, ASCII text)
	SSE016.TAZ	(new binaries, compressed tar file)

Checksums (sum -r):

    15726     5 sse016.ltr
    31228    64 sse016.tar.Z

V.   Updates

This bulletin is available for anonymous ftp download from
ftp://ftp.sco.COM/SSE/security_bulletins/SB-98.05a, and will be
updated as new information becomes available.

The latest information on security vulnerabilities and fixes from
SCO is available on the world-wide web at http://www.sco.com/security/

VI.  Further Information:

If you have further questions, contact your support provider.  If you
need to contact SCO, please send electronic mail to support@sco.COM, or
contact SCO as follows.

    USA/Canada: 6am-5pm Pacific Time (PST/PDT)
    -----------
    1-800-347-4381  (voice)
    1-408-427-5443  (fax)

    Pacific Rim, Asia, and Latin American customers: 6am-5pm Pacific
    ------------------------------------------------ Time (PST/PDT)
    1-408-425-4726  (voice)
    1-408-427-5443  (fax)

    Europe, Middle East, Africa: 9am-5:30pm UK Time (GMT/BST)
    ----------------------------
    +44 (0)1923 816344 (voice)
    +44 (0)1923 817781 (fax)


========================FORWARDED TEXT ENDS HERE=============================

If you believe that your system has been compromised, contact the CERT
Coordination Center or your representative in the Forum of Incident Response
and Security Teams (FIRST). See http://www.first.org/team-info/.

We strongly urge you to encrypt any sensitive information you send by email.
The CERT Coordination Center can support a shared DES key and PGP. Contact
the CERT staff for more information.

Location of CERT PGP key
         ftp://ftp.cert.org/pub/CERT_PGP.key


CERT Contact Information
- - ------------------------
Email    cert@cert.org

Phone    +1 412-268-7090 (24-hour hotline)
                CERT personnel answer 8:30-5:00 p.m. EST
                (GMT-5)/EDT(GMT-4), and are on call for
                emergencies during other hours.

Fax      +1 412-268-6989

Postal address
        CERT Coordination Center
        Software Engineering Institute
        Carnegie Mellon University
        Pittsburgh PA 15213-3890
        USA

CERT publications, information about FIRST representatives, and other
security-related information are available from
        http://www.cert.org/
        ftp://ftp.cert.org/pub/

CERT advisories and bulletins are also posted on the USENET newsgroup
        comp.security.announce

To be added to our mailing list for CERT advisories and bulletins, send your
email address to
        cert-advisory-request@cert.org
In the subject line, type
        SUBSCRIBE  your-email-address


==========================================================================
* Registered U.S. Patent and Trademark Office.

The CERT Coordination Center is part of the Software Engineering
Institute (SEI). The SEI is sponsored by the U. S. Department of Defense.


NO WARRANTY
ANY MATERIAL FURNISHED BY CARNEGIE MELLON UNIVERSITY AND THE SOFTWARE
ENGINEERING INSTITUTE IS FURNISHED ON AN "AS IS" BASIS. CARNEGIE MELLON
UNIVERSITY MAKES NO WARRANTIES OF ANY KIND, EITHER EXPRESSED OR IMPLIED AS TO
ANY MATTER INCLUDING, BUT NOT LIMITED TO, WARRANTY OF FITNESS FOR A PARTICULAR
PURPOSE OR MERCHANTABILITY, EXCLUSIVITY OR RESULTS OBTAINED FROM USE OF THE
MATERIAL. CARNEGIE MELLON UNIVERSITY DOES NOT MAKE ANY WARRANTY OF ANY KIND
WITH RESPECT TO FREEDOM FROM PATENT, TRADEMARK, OR COPYRIGHT INFRINGEMENT.

==========================================================================

This file: ftp://ftp.cert.org/pub/cert_bulletins/VB-98.10.sco.mscreen



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This security bulletin is provided as a service to AusCERT's members.  As
AusCERT did not write the document quoted above, AusCERT has had no control
over its content.  The decision to use any or all of this information is
the responsibility of each user or organisation, and should be done so in
accordance with site policies and procedures.

NOTE: This is only the original release of the security bulletin.  It will
not be updated when updates to the original are made.  If downloading at
a later date, it is recommended that the bulletin is retrieved directly
from the original authors to ensure that the information is still current.

Contact information for the authors of the original document is included
in the Security Bulletin above.  If you have any questions or need further
information, please contact them directly.

Previous advisories and external security bulletins can be retrieved from:

	http://www.auscert.org.au/Information/advisories.html

If you believe that your system has been compromised, contact AusCERT or
your representative in FIRST (Forum of Incident Response and Security
Teams).

Internet Email: auscert@auscert.org.au
Facsimile:	(07) 3365 7031
Telephone:	(07) 3365 4417 (International: +61 7 3365 4417)
		AusCERT personnel answer during Queensland business hours
		which are GMT+10:00 (AEST).
		On call after hours for emergencies.


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