AUSCERT External Security Bulletin Redistribution

              ESB-97.119 -- SGI Security Advisory 19970508-02-PX 
                  IRIX LOCKOUT and login/scheme Buffer Overrun
                              16 September 1997


Silicon Graphics Inc.  has released the following advisory concerning two
vulnerabilities in the IRIX login program.  These vulnerabilities have
been previously described in AUSCERT advisories AA-97.12 "SGI IRIX login
LOCKOUT parameter Vulnerability" and AA-97.22 "SGI IRIX login/scheme Buffer
Overrun Vulnerability".

The LOCKOUT parameter vulnerability (AA-97.12) may allow users to create
arbitrary or corrupt certain files on the system.

The login/scheme buffer overrun vulnerability (AA-97.22) may allow local
users to gain root privileges.

The following security bulletin is provided as a service to AUSCERT's
members.  As AUSCERT did not write this document, AUSCERT has had no
control over its content.  As such, 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.

Contact information for SGI is included in the Security Bulletin below.
If you have any questions or need further information, please contact them

Previous advisories and external security bulletins can be retrieved from:


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

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.

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                Silicon Graphics Inc. Security Advisory

        Title:   IRIX LOCKOUT and login/scheme Buffer Overrun
        Title:   AUSCERT AA-97.12 and CERT CA-97.15
        Title:   AUSCERT AA-97.22 and CERT CA-97.21
        Number:  19970508-02-PX
        Date:    September 15, 1997

Silicon Graphics provides this information freely to the SGI user community
for its consideration, interpretation, implementation and use.   Silicon
Graphics recommends that this information be acted upon as soon as possible.

Silicon Graphics provides the information in this Security Advisory on
an "AS-IS" basis only, and disclaims all warranties with respect thereto,
express, implied or otherwise, including, without limitation, any warranty
of merchantability or fitness for a particular purpose.  In no event shall
Silicon Graphics be liable for any loss of profits, loss of business, loss
of data or for any indirect, special, exemplary, incidental or consequential
damages of any kind arising from your use of, failure to use or improper
use of any of the instructions or information in this Security Advisory.

- - -----------------------
- - --- Issue Specifics ---
- - -----------------------

This advisory covers two security issues that were public reported as
two different issues.  Both these issues have been addressed together
by Silicon Graphics.

The first issue has to do with the LOCKOUT functionality of the login(1)
program.  When the LOCKOUT value is set to a value greater than zero, an
account will be locked when that value of unsuccessful login attempts
has been made by the same user.  Due to an error in the login verification
process when LOCKOUT is enabled, files may be created or corrupted.
This resulting file manipulation is considered a security vulnerability.

The second related issue has to do with the login(1) program itself.
Actually, the /usr/bin/login file is a symbolic link to the
/usr/lib/iaf/scheme that is used at the startup of all terminal sessions
to identify users to each session.  Since arguments can be given to this
program as part of use, it has been determined that an appropriately
crafted set of arguments could be input to the login/scheme program
allowing execution of arbitrary user commands with root privileges.
This resulting buffer overflow condition is considered a security

Silicon Graphics Inc. has investigated these issues and recommends the
following steps for neutralizing the exposure.  It is HIGHLY RECOMMENDED
that these measures be implemented on ALL SGI systems.  These issues will
be corrected in future releases of IRIX.

- - --------------
- - --- Impact ---
- - --------------

The scheme program and login symbolic link to the scheme program are
installed by default on all IRIX systems.   The LOCKOUT variable
in the /etc/default/login is set to zero as default.

For these vulnerabilities, a local account is not required.
Furthermore, the vulnerabilities can be exploited remotely.

A local account is required in order to exploit these vulnerabilities
both locally and remotely.

Utilizing the LOCKOUT vulnerability, random files can be created
and corrupted.

Both of these security issues have been publically disclosed and
discussed in several public forums including the BUGTRAQ mailing list.
Additionally, security advisories AUSCERT AA-97.12, CERT CA-97.15,
AUSCERT AA-97.22 and CERT CA-97.21 have been publically released
on the issues.

- - --------------------------
- - --- Temporary Solution ---
- - --------------------------

Although patches are available for this issue, it is realized that
there may be situations where installing the patches immediately may
not be possible.

Although there are no SGI provided workarounds for the login/scheme
issue, the steps below can be used to remove the LOCKOUT vulnerability
by disabling the LOCKOUT functionality.

     1) Become the root user on the system.

                % /bin/su -

     2) Edit the file /etc/default/login and place a "#" as
     the first character of the LOCKOUT line to comment out
     and deactivate the service.

                # vi  /etc/default/login

        {Find the following line}


        {The value can be any number greater than 0.}
        {Place a "#" as the first character of the LOCKOUT line}


        {Save the file and exit}

     4) Return to previous level.

                # exit

- - ----------------
- - --- Solution ---
- - ----------------

Since two security issues are addressed with the following patches,
the "Vulnerable?" column below means that either one or both of
the vulnerabilities exist in that OS version.

   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          2216
   IRIX 6.0.x        yes          not avail    Note 1
   IRIX 6.1          yes          not avail    Note 1
   IRIX 6.2          yes          2181
   IRIX 6.3          yes          2232
   IRIX 6.4          yes          2233


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

Patches are available via anonymous FTP and your service/support provider.

The SGI anonymous FTP site is sgigate.sgi.com ( or its
mirror, ftp.sgi.com.   Security information and patches can be found
in the ~ftp/security and ~ftp/patches directories, respectfully.

                 ##### Patch File Checksums ####

The actual patch will be a tar file containing the following files:

Filename:                 README.patch.2216
Algorithm #1 (sum -r):    13912 12 README.patch.2216
Algorithm #2 (sum):       20179 12 README.patch.2216
MD5 checksum:             FA1A32EE675B3719020F845B4C0B8F45

Filename:                 patchSG0002216
Algorithm #1 (sum -r):    03669 3 patchSG0002216
Algorithm #2 (sum):       18776 3 patchSG0002216
MD5 checksum:             7DA08E2147BEB9E49229B015DCB61895

Filename:                 patchSG0002216.eoe1_man
Algorithm #1 (sum -r):    31290 33 patchSG0002216.eoe1_man
Algorithm #2 (sum):       62564 33 patchSG0002216.eoe1_man
MD5 checksum:             8EEF9215B03E7DB99D8011D41B7D6E1B

Filename:                 patchSG0002216.eoe1_sw
Algorithm #1 (sum -r):    27451 73 patchSG0002216.eoe1_sw
Algorithm #2 (sum):       3649 73 patchSG0002216.eoe1_sw
MD5 checksum:             5C38961E861E986DE49EFF5C3BECD641

Filename:                 patchSG0002216.eoe2_sw
Algorithm #1 (sum -r):    22903 46 patchSG0002216.eoe2_sw
Algorithm #2 (sum):       55667 46 patchSG0002216.eoe2_sw
MD5 checksum:             BFCE3A01BB0181626E79E584EB19525B

Filename:                 patchSG0002216.idb
Algorithm #1 (sum -r):    12991 3 patchSG0002216.idb
Algorithm #2 (sum):       18240 3 patchSG0002216.idb
MD5 checksum:             E384459949E4B24C34591C786367B050

Filename:                 README.patch.2181
Algorithm #1 (sum -r):    40529 10 README.patch.2181
Algorithm #2 (sum):       15557 10 README.patch.2181
MD5 checksum:             7FBE5B1971162512C1D409E6D4BB9C71

Filename:                 patchSG0002181
Algorithm #1 (sum -r):    40880 2 patchSG0002181
Algorithm #2 (sum):       60865 2 patchSG0002181
MD5 checksum:             1F5CAA24C48D48D586486009871F275E

Filename:                 patchSG0002181.eoe_man
Algorithm #1 (sum -r):    12558 35 patchSG0002181.eoe_man
Algorithm #2 (sum):       44605 35 patchSG0002181.eoe_man
MD5 checksum:             F6A9E5B102B1911074D1B1A34E351A05

Filename:                 patchSG0002181.eoe_sw
Algorithm #1 (sum -r):    24729 73 patchSG0002181.eoe_sw
Algorithm #2 (sum):       474 73 patchSG0002181.eoe_sw
MD5 checksum:             B92BC59995D99EFB60160F208F9A71B9

Filename:                 patchSG0002181.idb
Algorithm #1 (sum -r):    19924 2 patchSG0002181.idb
Algorithm #2 (sum):       59251 2 patchSG0002181.idb
MD5 checksum:             4EAE11E46FFAC4B09963C6BE466A7A72

Filename:                 README.patch.2232
Algorithm #1 (sum -r):    30727 12 README.patch.2232
Algorithm #2 (sum):       55743 12 README.patch.2232
MD5 checksum:             DD9402D2434B1513A3B9886D70CD9243

Filename:                 patchSG0002232
Algorithm #1 (sum -r):    55916 3 patchSG0002232
Algorithm #2 (sum):       20486 3 patchSG0002232
MD5 checksum:             FE63680542E429EA91D33AA15EB06537

Filename:                 patchSG0002232.eoe_man
Algorithm #1 (sum -r):    43804 36 patchSG0002232.eoe_man
Algorithm #2 (sum):       27383 36 patchSG0002232.eoe_man
MD5 checksum:             6EE21B2D5362295BDC20D5F84BA7DEC4

Filename:                 patchSG0002232.eoe_sw
Algorithm #1 (sum -r):    03690 421 patchSG0002232.eoe_sw
Algorithm #2 (sum):       11833 421 patchSG0002232.eoe_sw
MD5 checksum:             C5AD8C10999347F8FA67871B5B98CB63

Filename:                 patchSG0002232.idb
Algorithm #1 (sum -r):    38374 4 patchSG0002232.idb
Algorithm #2 (sum):       4337 4 patchSG0002232.idb
MD5 checksum:             0610B31450652A09F343E2B1ED3E939A

Filename:                 README.patch.2233
Algorithm #1 (sum -r):    51881 11 README.patch.2233
Algorithm #2 (sum):       41695 11 README.patch.2233
MD5 checksum:             5D7F90A9AE9F2A483059E6D8D08DF317

Filename:                 patch2233.pgp.and.chksums
Algorithm #1 (sum -r):    00000 0 patch2233.pgp.and.chksums
Algorithm #2 (sum):       0 0 patch2233.pgp.and.chksums
MD5 checksum:             D41D8CD98F00B204E9800998ECF8427E

Filename:                 patchSG0002233
Algorithm #1 (sum -r):    18405 3 patchSG0002233
Algorithm #2 (sum):       23610 3 patchSG0002233
MD5 checksum:             462695A8E5958C4B6A78960F001A2351

Filename:                 patchSG0002233.eoe_man
Algorithm #1 (sum -r):    43804 36 patchSG0002233.eoe_man
Algorithm #2 (sum):       27383 36 patchSG0002233.eoe_man
MD5 checksum:             6EE21B2D5362295BDC20D5F84BA7DEC4

Filename:                 patchSG0002233.eoe_sw
Algorithm #1 (sum -r):    24542 347 patchSG0002233.eoe_sw
Algorithm #2 (sum):       6782 347 patchSG0002233.eoe_sw
MD5 checksum:             B5D1408146E7B71B1F5A8290ABCF5A4F

Filename:                 patchSG0002233.idb
Algorithm #1 (sum -r):    50085 3 patchSG0002233.idb
Algorithm #2 (sum):       41850 3 patchSG0002233.idb
MD5 checksum:             B41E8A31941E47BD46682CFB4641882F

- - ------------------------
- - --- Acknowledgments ---
- - ------------------------

Silicon Graphics Inc. wishes to thank AUSCERT and the CERT Coordination
Center and the Internet community for their assistance in these issues.

- - -----------------------------------------------------------
- - --- Silicon Graphics Inc. Security Information/Contacts ---
- - -----------------------------------------------------------

If there are questions about this document, email can be sent to


Silicon Graphics provides security information and patches for
use by the entire SGI community.  This information is freely
available to any person needing the information and is available
via anonymous FTP and the Web.

The primary SGI anonymous FTP site for security information and patches
is sgigate.sgi.com (  Security information and patches
are located under the directories ~ftp/security and ~ftp/patches,
respectively. The Silicon Graphics Security Headquarters Web page is
accessible at the URL http://www.sgi.com/Support/security/security.html.

For issues with the patches on the FTP sites, email can be sent to

For assistance obtaining or working with security patches, please
contact your SGI support provider.


Silicon Graphics provides a free security mailing list service
called wiretap and encourages interested parties to self-subscribe
to receive (via email) all SGI Security Advisories when they are
released. Subscribing to the mailing list can be done via the Web
(http://www.sgi.com/Support/security/wiretap.html) or by sending email
to SGI as outlined below.

% mail wiretap-request@sgi.com
subscribe wiretap <YourEmailAddress>

In the example above, <YourEmailAddress> is the email address that you
wish the mailing list information sent to.  The word end must be on a
separate line to indicate the end of the body of the message. The
control-d (^d) is used to indicate to the mail program that you are
finished composing the mail message.


Silicon Graphics provides a comprehensive customer World Wide Web site.
This site is located at http://www.sgi.com/Support/security/security.html.


For reporting *NEW* SGI security issues, email can be sent to
security-alert@sgi.com or contact your SGI support provider.  A
support contract is not required for submitting a security report.

  This information is provided freely to all interested parties and may
  be redistributed provided that it is not altered in any way, Silicon
  Graphics is appropriately credited and the document retains and
  includes its valid PGP signature.

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