Sun Security Bulletin #00147

[aleph1 () DFW NET (Aleph One)]

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________________________________________________________________________________
                   Sun Microsystems, Inc. Security Bulletin

Bulletin Number:        #00147
Date:                   July 24, 1997
Cross-Ref:              AUSCERT AA-97.01, CERT CA-97.04
Title:                  Vulnerability in talkd

________________________________________________________________________________
Permission is granted for the redistribution of this Bulletin, so long as
the Bulletin is not edited and is attributed to Sun Microsystems. Portions
may also be excerpted for re-use in other security advisories so long as
proper attribution is included.

Any other use of this information without the express written consent of
Sun Microsystems is prohibited. Sun Microsystems expressly disclaims all
liability for any misuse of this information by any third party.
________________________________________________________________________________

1.  Bulletins Topics

    Sun announces the release of patches for Solaris 2.5.1, 2.5, 2.4, and 2.3
    (SunOS 5.5.1, 5.5, 5.4, and 5.3), SunOS 4.1.4 and 4.1.3_U1 which relate to
    a vulnerability in the talkd program.

    Sun strongly recommends that you install the patches listed in section 4
    immediately on systems running SunOS 5.5.1, 5.5, 5.4, 5.3, 4.1.4, and
    4.1.3_U1. Exploit information is publicly available.

2.  Who is Affected

    Vulnerable:  SunOS versions 5.5.1, 5.5.1_x86, 5.5, 5.5_x86,
                                5.4, 5.4_x86, 5.3, 4.1.4, and 4.1.3_U1

    The vulnerability is fixed in the upcoming release of Solaris.

3.  Understanding the Vulnerability

    The program talk provides a two-way, screen-oriented conversation between
    users. The daemon talkd notitifes a user that another user wishes to
    initiate a talk conversation. When a user initiates a talk conversation,
    talkd performs a name service lookup for the name of the initiating host.
    Due to insufficient bounds checking on the buffer where the hostname is
    stored, it is possible to overwrite the internal stack space of the talkd
    program. As talkd is setuid root, this vulnerability may be exploited by
    intruders to remotely execute arbitrary commands with root privileges. To
    exploit this vulnerability, attackers have to be able to make a network
    connection to the vulnerable talkd program and provide corrupt hostname
    information to that host.

4.  List of Patches

    The vulnerability in talkd is fixed by the following patches:

    OS version          Patch ID
    __________          ________
    SunOS 5.5.1         104692-01
    SunOS 5.5.1_x86     104693-01
    SunOS 5.5           104690-01
    SunOS 5.5_x86       104691-01
    SunOS 5.4           104701-01
    SunOS 5.4_x86       104702-01
    SunOS 5.3           104698-01
    SunOS 4.1.4         104998-01
    SunOS 4.1.3_U1      104997-01

5.  Checksum Table

    The checksum table below shows the BSD checksums (SunOS 4.1.x: /bin/sum;
    SunOS 5.x: /usr/ucb/sum), SVR4 checksums (SunOS 5.x: /usr/bin/sum), and
    the MD5 digital signatures for the above-mentioned patches that are
    available from:

        <URL:ftp://sunsolve1.sun.com/pub/patches/patches.html>

    These checksums may not apply if you obtain patches from your answer
    centers.

File Name         BSD        SVR4         MD5
_______________   ________   _________    ________________________________
104692-01.tar.Z   05337 97   5296 194     0F45E5B9CCAD276AE166CAFFE9110799
104693-01.tar.Z   44228 97   39970 194    32D62F61E350AA6B50FBD2A4BA1059CA
104690-01.tar.Z   26808 97   47810 194    E4360074D6BB751C22406F1962556138
104691-01.tar.Z   07788 97   37926 194    B3519CA85BCD2CD818B1712B655E260F
104701-01.tar.Z   03035 85   2323 169     FCBEEAADE24029B9E5B0FB3CFAEE9CCE
104702-01.tar.Z   14433 85   29616 169    922599D5FF853181A9671070C7213F0D
104698-01.tar.Z   25487 85   52869 169    337DD394B381E4D61BA7E590ED1BBAD7
104998-01.tar.Z   46836 10   15721 19     8C62C5B5E0965BB0E0D3B5B835D98670
104997-01.tar.Z   21171 10   10506 19     DE1AE78A37570FD597AA39844554A3C7
________________________________________________________________________________
Sun acknowledges with thanks AUSCERT and CERT/CC for their assistance in the
preparation of this bulletin.

Sun, AUSCERT, and CERT/CC are members of FIRST, the Forum of Incident Response
and Security Teams. For more information about FIRST, visit the FIRST web site
at "http://www.first.org/";.
________________________________________________________________________________
APPENDICES

A.  Patches listed in this bulletin are available to all Sun customers via
    World Wide Web at:

        <URL:ftp://sunsolve1.sun.com/pub/patches/patches.html>

    Customers with Sun support contracts can also obtain patches from local
    Sun answer centers and SunSITEs worldwide.

B.  Sun security bulletins are available via World Wide Web at:

        <URL:http://sunsolve1.sun.com/sunsolve/secbulletins>

C.  To report or inquire about a security problem with Sun software, contact
    one or more of the following:

        - Your local Sun answer centers
        - Your representative computer security response team, such as CERT
        - Sun Security Coordination Team. Send email to:

                security-alert () sun com

D.  To receive information or subscribe to our CWS (Customer Warning System)
    mailing list, send email to:

                security-alert () sun com

    with a subject line (not body) containing one of the following commands:

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________________________________________________________________________________



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