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=============================================================================
CERT(*) Advisory CA-96.27
Original issue date: December 19, 1996
Last Revised: September 24, 1997
        Updated copyright statement

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

Topic: Vulnerability in HP Software Installation Programs

- -----------------------------------------------------------------------------

   The text of this advisory was originally released on October 11, 1996, as
   AA-96.04.Vulnerability.in.HP.Software.Installation.Programs, developed by
   AUSCERT. Because of the seriousness of the problem, we are reprinting the
   AUSCERT advisory here with their permission. Only the contact information
   at the end has changed: AUSCERT contact information has been replaced with
   CERT/CC contact information.

   We will update this advisory as we receive additional information.
   Look for it in an "Updates" section at the end of the advisory.

===========================================================================
AA-96.04                        AUSCERT Advisory
               Vulnerability in HP Software Installation Programs
                                 11 October 1996



- ----------------------------------------------------------------------------

AUSCERT has received information that there is a vulnerability in the
Hewlett Packard Software Distributor product, SD-UX, used to install,
update, remove and package HP-UX software and patches.  This software is
installed by default under HP-UX 10.x and may have been specifically
installed as additional software under HP-UX 9.x.  Any system with the
SD-UX package installed is vulnerable.

This vulnerability may allow local users to gain root privileges.

Exploit details involving this vulnerability have been made publicly
available.

Vendor patches are being developed, but until they are made available,
AUSCERT recommends that sites take the actions suggested in Section 3.

- ----------------------------------------------------------------------------

1.  Description

    The HP Software Distributor (SD-UX) is a package that provides a user
    interface which can be used to install, update, remove, and package HP-UX
    software and patches.

    The programs supplied with this package create files in an insecure
    manner.  As these programs execute with root privileges, it is possible
    to create or over-write arbitrary files on the system.  The default
    location of the programs supplied by the package is /usr/sbin.

    To determine if you have SD-UX installed on your system, check for
    the presence of the swinstall (and related) files using the
    following command:

        % ls -l /usr/sbin/sw*

    Individual sites are encouraged to check their systems for the SD-UX
    package, and if installed, take the actions recommended in Section 3.


2.  Impact

    Local users may be able to create or over-write arbitrary files on
    the system.  This can be leveraged to gain root privileges.


3.  Workarounds/Solution

    AUSCERT recommends that sites prevent possible exploitation of this
    vulnerability by taking the measures stated in Section 3.1 immediately.

    If software maintenance is required, AUSCERT advises that sites
    use one of the workarounds given in 3.2, preferably that described in
    Section 3.2.1.

    Vendor patches may also address this vulnerability in the
    future (Section 3.3).

 3.1 Remove permissions

     Until official patches are available sites are encouraged to completely
     prevent the execution of all vulnerable SD-UX programs by any user
     (including root).

   # chmod 400 /usr/sbin/swinstall
   # chmod 400 /usr/sbin/swmodify

     Note that if only the setuid permissions are removed, it is still
     possible for users to gain the privileges of any user executing
     the SD-UX programs (including root).


 3.2 Workarounds

     AUSCERT recommends that if software maintenance is required, sites
     implement one of the following workarounds until official vendor
     patches are made available.

     The workaround described in 3.2.1 is the preferred method of doing
     software maintenance.  If sites are unable to bring their machines
     into single user mode, the workaround given in Section 3.2.2 may be
     more applicable.

 3.2.1  Run in single user mode

     If packages must be installed, the machine should be brought into
     single-user mode, execute permissions re-enabled on
     /usr/sbin/swinstall,

   # chmod 700 /usr/sbin/swinstall
   # chmod 700 /usr/sbin/swmodify

     and all symbolic links in /var/tmp and /tmp removed.  The following
     command can be used to remove the symbolic links:

   # find /tmp /var/tmp -type l -ok rm {} \;

     Once this has been completed, any software package maintenance may be
     safely performed.

     The execute permissions on the vulnerable programs must be removed
     before the machine is brought back into multi-user mode.

   # chmod 400 /usr/sbin/swinstall
   # chmod 400 /usr/sbin/swmodify

 3.2.2 Change temporary file environment variable

     This workaround should only be used if the SD-UX programs must be used
     while the machine is in multi-user mode.

     The SD-UX programs use a number of temporary files.  The location of
     these files can be configured using the environment variable TMPDIR.
     It is possible to set the environment variable TMPDIR to a non-world
     writable directory.  Having the temporary files created in a non-world
     writable directory prevents the exploitation of the vulnerability
     described in this advisory.

     NOTE:  The environment variable must be set in each login
      session BEFORE any SD-UX programs are used.

     To use this method, the following steps must be taken:

     1) As root, create a non-world writable temporary directory for the
     temporary files used by the SD-UX programs.  The location of these
     temporary files can be configured with the TMPDIR environment variable.
     In this workaround, we have chosen to use the directory
     /var/tmp/SD_tmp.

   # mkdir /var/tmp/SD_tmp
   # chmod 700 /var/tmp/SD_tmp

     For this workaround to be effective, sites should ensure that the
     parent directory of $TMPDIR has the sticky bit set if the parent
     directory is world writable.  In this workaround, /var/tmp is the
     directory concerned.  The sticky bit on /var/tmp can be set with the
     command:

   # chmod 1777 /var/tmp


     In all sessions where software maintenance is performed:

     2) Change permissions on the vulnerable programs:

   # chmod 700 /usr/sbin/swinstall
   # chmod 700 /usr/sbin/swmodify

     3) Set the environment variable TMPDIR:

   (under csh)
   # setenv TMPDIR /var/tmp/SD_tmp

   (under sh)
   # TMPDIR=/var/tmp/SD_tmp; export TMPDIR

  and verify that the directory exists and is writable by root.

   # ls -ld $TMPDIR

      4) Perform any software package maintenance.

      5) Remove the execute permissions on the vulnerable programs:

   # chmod 400 /usr/sbin/swinstall
   # chmod 400 /usr/sbin/swmodify

      6) The environment variable TMPDIR is used by many other programs.
      You should either exit this interactive session, or reset the
      TMPDIR environment variables before continuing.

      NOTE:  Steps 2) through 6) must be repeated each time software
       maintenance is performed.

 3.3 Install vendor patches

     Official vendor patches are currently being developed to address the
     vulnerability described in this advisory.  When vendor patches are
     made available, AUSCERT suggests that they be installed.


 ----------------------------------------------------------------------------
 AUSCERT thanks Information Technology Services of the University of Southern
 Queensland, Viviani Paz (The University of Queensland) and Hewlett Packard
 for their assistance in this matter.
 ----------------------------------------------------------------------------

 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).

 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://info.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 for anonymous FTP from
   https://www.cert.org/
   ftp://info.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

- ------------------------------------------------------------------------------

Copyright 1996, 1997 Carnegie Mellon University. Conditions for use,
disclaimers, and sponsorship information can be found in
https://www.cert.org/legal_stuff.html and ftp://ftp.cert.org/pub/legal_stuff .
If you do not have FTP or web access, send mail to cert@cert.org with
"copyright" in the subject line.

CERT is registered in the U.S. Patent and Trademark Office.


This file:
ftp://info.cert.org/pub/cert_advisories/CA-96.27.hp_sw_install

           https://www.cert.org
               click on "CERT Advisories"

=============================================================================
UPDATES

Hewlett-Packard
===============
  Information concerning patches for the vulnerability described in this
  advisory can be found in HEWLETT-PACKARD SECURITY BULLETIN,
  "Security Vulnerability in swinstall command," Document ID: HPSBUX9707-064

      1)  From your Web browser, access the URL:

          https://us-support.external.hp.com
          (for US,Canada, Asia-Pacific, and Latin-America)

          https://europe-support.external.hp.com  (for Europe)

      2)  On the HP Electronic Support Center main screen, select
          the hyperlink "Support Information Digests".

      3)  On the "Welcome to HP's Support Information Digests" screen,
          under the heading "Register Now", select the appropriate
          hyperlink "Americas and Asia-Pacific", or "Europe".

      4)  On the "New User Registration" screen, fill in the fields for
          the User Information and Password and then select the button
          labeled "Submit New User".

      5)  On the "User ID Assigned" screen, select the hyperlink
          "Support Information Digests".

          ** Note what your assigned user ID and password are for
            future reference.

      6)  You should now be on the "HP Support Information Digests Main"
          screen.  You might want to verify that your email address is
          correct as displayed on the screen.  From this screen, you may
          also view/subscribe to the digests, including the security
          bulletins digest.

      To get a patch matrix of current HP-UX and BLS security patches
      referenced by either Security Bulletin or Platform/OS, click on
      following screens in order:
         Technical Knowledge Database
         Browse Security Bulletins
         Security Bulletins Archive
         HP-UX Security Patch Matrix

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Revision history

Sep. 24, 1997  Updated copyright statement
July 28, 1997, Updates section - added information from Hewlett-Packard.

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