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AA-96.20                        AUSCERT Advisory
                         SGI IRIX datman/cdman Vulnerability
                                10 December 1996

Last Revised: 20 March 1998
              Changed Section 3 to include vendor patch and bulletin
              information.

              A complete revision history is at the end of this file.

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AUSCERT has received information that there is a vulnerability in the
datman(1) program distributed with IRIX 5.x and 6.x. datman is a
program used for playing audio tapes and CDs.

This vulnerability may allow local users to gain root privileges.

Exploit details involving this vulnerability have been widely distributed.

Vendor patches have been released addressing this vulnerability.

AUSCERT recommends that sites take the steps outlined in section 3 as
soon as possible.

This advisory will be updated as new information becomes available.

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1.  Description

    datman(1) is a program for playing audio tapes and CDs.  When called
    as datman it works as a tape recorder.  When called as cdman or when
    the -cd option is specified, datman works as a CD player.  By default,
    the file /usr/sbin/cdman is a symbolic link to /usr/sbin/datman.

    There is a vulnerability in datman that allows local users to execute
    arbitrary commands with root privileges.

    Exploit details involving this vulnerability have been made publicly
    available.

    This program may be installed under both IRIX 5.x and 6.x.  By default,
    it is installed under /usr/sbin/datman.  To determine whether the
    datman program is installed, sites should check for its presence
    with the command:

  % ls -l /usr/sbin/datman

    If this program is installed, sites should take the actions recommended
    in Section 3 immediately.

2.  Impact

    Local users may be able to run arbitrary commands with root privileges.

3.  Workarounds/Solution

    Official vendor patches have been released by Silicon Graphics which
    address this vulnerability (Section 3.2).

    If the patches recommended by Silicon Graphics cannot be applied,
    AUSCERT recommends that sites prevent the exploitation of this
    vulnerability by immediately applying the workaround given in Section
    3.1.

3.1 Remove setuid and execute permissions

    To prevent the exploitation of the vulnerability described in this
    advisory, sites should remove the setuid root and execute permissions
    from datman.  To do this, the following command should be run as
    root:

        # chmod 400 /usr/sbin/datman
  # ls -l /usr/sbin/datman
  -r--------    1 root   sys   795200 Nov 22  1994 /usr/sbin/datman

    Note that this will remove the ability for users to run this program.

3.2 Install vendor patches

    Silicon Graphics has released a security bulletin containing
    information about and patch details for similar vulnerabilities
    affecting a number of related programs including datman. The
    original release of this bulletin can be retrieved from: 
    
        ftp://sgigate.sgi.com/security/19980301-01-PX

    Information on patches which address the vulnerability described in
    this advisory has been extracted from the SGI bulletin and is listed
    below.

       OS Version     Vulnerable?     Patch #      Other Actions
       ----------     -----------     -------      -------------

       IRIX 3.x          no
       IRIX 4.x          no
       IRIX 5.0.x        yes          not avail    Note 1
       IRIX 5.1.x        yes          not avail    Note 1
       IRIX 5.2          yes          not avail    Note 1
       IRIX 5.3          yes          2563
       IRIX 6.0.x        yes          not avail    Note 1
       IRIX 6.1          yes          not avail    Note 1
       IRIX 6.2          yes          2564
       IRIX 6.3          yes          2565
       IRIX 6.4          yes          2291


       NOTES

         1) upgrade operating system or see "Temporary Solution" section.

    "Temporary Solution" refers to the SGI bulletin but is equivalent to
    the suggestions given in our AUSCERT advisory in section 3.1.

    These patches can be retrieved from:

        ftp://sgigate.sgi.com/patches/

4.  Additional measures

    Most Unix systems ship numerous programs which have setuid or
    setgid privileges.  Often the functionality supplied by these
    privileged programs is not required by many sites.  The large number
    of privileged programs that are shipped by default are to cater for
    all possible uses of the system.

    AUSCERT encourages sites to examine all the setuid/setgid programs
    and determine the necessity of each program.  If a program does not
    absolutely require the setuid/setgid privileges to operate (for
    example, it is only run by the root user),  the setuid/setgid
    privileges should be removed.  Furthermore, if a program is not
    required at your site, then all execute permissions should be removed.

    A sample command to find all setuid/setgid programs is (run as root):

       # find / \( -perm -4000 -o -perm -2000 \) -exec ls -ld {} \;

    It is AUSCERT's experience that many vulnerabilities are being
    discovered in setuid/setgid programs which are not necessary for the
    correct operation of most systems.  Sites can increase their security
    by removing unnecessary setuid/setgid programs.

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The AUSCERT team have made every effort to ensure that the information
contained in this document is accurate.  However, the decision to use the
information described is the responsibility of each user or organisation.
The appropriateness of this document for an organisation or individual
system should be considered before application in conjunction with local
policies and procedures.  AUSCERT takes no responsibility for the
consequences of applying the contents of this document.

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

AUSCERT is located at The University of Queensland within the Prentice
Centre.  AUSCERT is a full member of the Forum of Incident Response and
Security Teams (FIRST).

AUSCERT maintains an anonymous FTP service which is found on:
ftp://ftp.auscert.org.au/pub/.  This archive contains past SERT and AUSCERT
Advisories, and other computer security information.

AUSCERT also maintains a World Wide Web service which is found on:
http://www.auscert.org.au/.

Internet Email: auscert@auscert.org.au
Facsimile:  (07) 3365 4477
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.

Postal:
Australian Computer Emergency Response Team
c/- Prentice Centre
The University of Queensland
Brisbane
Qld.  4072.
AUSTRALIA


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Revision History

20 March 1998 Silicon Graphics has released a security bulletin
              addressing the vulnerability described in this advisory.
              Section 3 has been modified to include vendor patch
              information.


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