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SunOS : Four Vulnerabilities in the Common Desktop Environment



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Date: Mon, 13 Sep 1999 17:30:32 -0400
Message-Id: <199909132130.RAA21528@coal.cert.org>
From: CERT Advisory <cert-advisory@cert.org>
To: cert-advisory@coal.cert.org
Subject: CERT Advisory CA-99.11 - Four Vulnerabilities in the Common Desktop Environment
Reply-To: cert-advisory-request@cert.org
Organization: CERT(sm) Coordination Center -  +1 412-268-7090

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CERT Advisory CA-99-11 Four Vulnerabilities in the Common Desktop Environment

   Original release date: September 13, 1999
   Last revised: September 13, 1999
   Source: CERT/CC
   
   A complete revision history is at the end of this file.
   
Systems Affected

     * Systems running the Common Desktop Environment (CDE)
       
I. Description

   Multiple vulnerabilities have been identified in some distributions of
   the Common Desktop Environment (CDE). These vulnerabilities are
   different from those discussed in CA-98.02. We recommend that you
   install appropriate vendor patches as soon as possible (see Section
   III below). Until you can do so, we encourage you to disable or
   uninstall vulnerable copies of the CDE package. Note that disabling
   these programs will severely affect the utility of the CDE
   environment.
   
   At this time, the CERT/CC has not received any reports of these
   vulnerabilities being exploited by intruders.
   
Vulnerability #1: ToolTalk ttsession uses weak RPC authentication mechanism

   The ToolTalk messaging server ttsession allows independent
   applications to communicate without having direct knowledge of each
   other. Applications can communicate through an associated ttsession
   which delivers messages via RPC calls between interested agents.
   
   On many systems, ttsession uses AUTH_UNIX authentication (a
   client-based security option) by default. When messages are received,
   ttsession uses certain environment variables supplied by the client
   to determine how the message is handled. Because of this, the
   ttsession process can be manipulated to execute unauthorized
   arbitrary programs with the privileges of the running ttsession.
   
Vulnerability #2: CDE dtspcd relies on file-system based authentication

   The network daemon dtspcd (a CDE desktop subprocess control program)
   accepts CDE requests from clients to execute commands and launch
   applications remotely.
   
   When a client makes a request, the dtspcd daemon asks the client to
   create a file that has a predictable name so that the daemon can
   authenticate the request. If a local user can manipulate the files
   used for authentication, then that user can craft arbitrary commands
   that may run as root.
   
Vulnerability #3: CDE dtaction buffer overflow

   The dtaction utility allows applications or shell scripts that
   otherwise are not connected into the CDE development environment, to
   request that CDE actions be performed.
   
   A buffer overflow can occur in some implementations of dtaction when a
   username argument greater than 1024 bytes is used.
   
Vulnerability #4: CDE ToolTalk shared library buffer overflow in TT_SESSION

   There is a vulnerability in some implementations of the ToolTalk
   shared library which allows the TT_SESSION environment variable buffer
   to overflow. A setuid root program using a vulnerable ToolTalk
   library, such as dtsession, can be exploited to run arbitrary code as
   root.
   
II. Impact

Vulnerability #1: ToolTalk ttsession uses weak RPC authentication mechanism

   A local or remote user may be able to use this vulnerability to run
   commands on a vulnerable system with the same privileges of the
   attacked ttsession. For this attack to work, a ttsession must be
   actively running on the system attacked. The ttsession daemon is
   started whenever a user logs in using the CDE desktop, or upon
   interaction with CDE at some future point.
   
Vulnerability #2: CDE dtspcd relies on file-system based authentication

   A vulnerable dtspcd may allow a local user to run arbitrary commands
   as root.
   
Vulnerability #3: CDE dtaction buffer overflow

   A local user may be able to exploit this vulnerability to execute
   arbitrary code with root privileges.
   
Vulnerability #4: CDE ToolTalk shared library buffer overflow in TT_SESSION

   A local user may be able to exploit this vulnerability to execute
   arbitrary code with root privileges.
   
III. Solution

Install appropriate patches from your vendor

We recommend installing vendor patches as soon as possible and disabling the
vulnerable programs until you can do so (or uninstalling the entire CDE
package if not needed). Note that disabling these programs will severely
affect the utility of the CDE environment.

Appendix A contains information provided by vendors for this advisory. We
will update the appendix as we receive more information. If you do not see
your vendor's name, the CERT/CC did not hear from that vendor. Please
contact your vendor directly.

Appendix A. Vendor Information

Compaq Computer Corporation

   Problem #1 
          
          CDE ToolTalk session daemon & ToolTalk shared library overflow
          
          This potential security problem has been resolved and a patch
          for this problem has been made available for Tru64 UNIX V4.0D,
          V4.0E, V4.0F and V5.0.
          
          This patch can be installed on:
          
 V4.0D-F, all patch kits
 V5.0, all patch kits

          *This solution will be included in a future distributed release
          of Compaq's Tru64/ DIGITAL UNIX.
          
          This patch may be obtained from the World Wide Web at the
          following FTP address:
          
          http://www.service.digital.com/patches
          
          The patch file name is SSRT0617_ttsession.tar.Z
          
          Problem #2 
          
          Compaq's Tru64/DIGITAL UNIX is not vulnerable.
          
          Problem #3 
          
          CDE dtaction buffer overflow
          
          This potential security problem has been resolved and a patch
          for this problem has been made available for Tru64 UNIX V4.0D,
          V4.0E and V4.0F.
          
          This patch can be installed on:
          
V4.0D Patch kit BL11 or BL12
V4.0E Patch kit BL1 or BL12
V4.0F Patch kit BL1

          *This solution will be included in a future distributed release
          of Compaq's Tru64/ DIGITAL UNIX.
          
          This patch may be obtained from the World Wide Web at the
          following FTP address:
          
          http://www.service.digital.com/patches
          
          The patch file name is SSRT0615U_dtaction.tar.Z
          
          Problem #4 
          
          CDE ToolTalk shared library overflow
          
          See solution fix described in in Problem #1.
          
Fujitsu

   Fujitsu's UXP/V operating system is not vulnerable to any of these
          vulnerabilities.
          
   Hewlett-Packard Company
   
   HP-9000 Series 700/800 HP-UX releases 10.X and 11.0 systems with CDE
          patches previously recommended in HP Security Bulletins are not
          vulnerable to vulnerabilities #2, #3, and #4.
          
          All HP-UX 10.X and 11.0 systems running CDE are vulnerable to
          vulnerability #1.
          
          Patches are in progress.
          
   IBM Corporation
   
   All releases of AIX version 4 are vulnerable to vulnerabilities #1,
          #3, and #4. AIX is not vulnerable to #2. The following APARs
          will be available soon:
          
      AIX 4.1.x:  IY03125  IY03847
      AIX 4.2.x:  IY03105  IY03848
      AIX 4.3.x:  IY02944  IY03849

          Customers that do not require the CDE desktop functionality can
          disable CDE by restricting access to the CDE daemons and
          removing the dt entry from /etc/inittab. Run the following
          commands as root to disable CDE:
          
      # /usr/dt/bin/dtconfig -d
      # chsubserver -d -v dtspc
      # chsubserver -d -v ttdbserver
      # chsubserver -d -v cmsd
      # chown root.system /usr/dt/bin/*
      # chmod 0 /usr/dt/bin/*

          For customers that require the CDE desktop functionality, a
          temporary fix is available via anonymous ftp from:
          
          ftp://aix.software.ibm.com/aix/efixes/security/cdecert.tar.Z
          
   Filename        sum             md5
   =================================================================
   dtaction_4.1    32885    18     82af470bbbd334b240e874ff6745d8ca
   dtaction_4.2    52162    18     b10f21abf55afc461882183fbd30e602
   dtaction_4.3    56550    19     6bde84b975db2506ab0cbf9906c275ed
   libtt.a_4.1     29234  2132     f5d5a59956deb8b1e8b3a14e94507152
   libtt.a_4.2     21934  2132     73f32a73873caff06057db17552b8560
   libtt.a_4.3     12154  2118     b0d14b9fe4a483333d64d7fd695f084d
   ttauth          56348    31     495828ea74ec4c8f012efc2a9e6fa731
   ttsession_4.1   19528   337     bfac4a06b90cbccc0cd494a44bd0ebc9
   ttsession_4.2   46431   338     05949a483c4e390403055ff6961b0816
   ttsession_4.3   54031   339     e1338b3167c7edf899a33520a3adb060

          NOTE - This temporary fix has not been fully regression tested.
          Use the following steps (as root) to install the temporary fix.
          
   1. Uncompress and extract the fix.

      # uncompress < cdecert.tar.Z | tar xf -
      # cd cdecert

   2. Replace the vulnerable executables with the temporary fix for
      your version of AIX.

      # (cd /usr/dt/lib && mv libtt.a libtt.a.before_security_fix)
      # (cd /usr/dt/bin && mv ttsession ttsession.before_security_fix)
      # (cd /usr/dt/bin && mv dtaction dtaction.before_security_fix)
      # chown root.system /usr/dt/lib/libtt.a.before_security_fix
      # chown root.system /usr/dt/bin/ttsession.before_security_fix
      # chown root.system /usr/dt/bin/dtaction.before_security_fix
      # chmod 0 /usr/dt/lib/libtt.a.before_security_fix
      # chmod 0 /usr/dt/bin/ttsession.before_security_fix
      # chmod 0 /usr/dt/bin/dtaction.before_security_fix
      # cp ./libtt.a_ /usr/dt/lib/libtt.a
      # cp ./ttsession_ /usr/dt/bin/ttsession
      # cp ./dtaction_ /usr/dt/bin/dtaction
      # cp ./ttauth /usr/dt/bin/ttauth
      # chmod 555 /usr/dt/lib/libtt.a
      # chmod 555 /usr/dt/bin/ttsession
      # chmod 555 /usr/dt/bin/dtaction
      # chmod 555 /usr/dt/bin/ttauth

          IBM AIX APARs may be ordered using Electronic Fix Distribution
          (via the FixDist program), or from the IBM Support Center. For
          more information on FixDist, and to obtain fixes via the
          Internet, please reference
          
          http://techsupport.services.ibm.com/support/rs6000.support/down
          loads
          
          or send electronic mail to "aixserv@austin.ibm.com" with the
          word "FixDist" in the "Subject:" line. To facilitate ease of
          ordering all security related APARs for each AIX release,
          security fixes are periodically bundled into a cumulative APAR.
          For more information on these cumulative APARs including last
          update and list of individual fixes, send electronic mail to
          "aixserv@austin.ibm.com" with the word "subscribe
          Security_APARs" in the "Subject:" line.
          
   Santa Cruz Operation, Inc.
   
   SCO is investigating these vulnerabilities on SCO UnixWare 7. Other
          SCO products (OpenServer 5.0.x, UnixWare 2.1.x, Open Server /
          Open Desktop 3.0 and CMW+) are not vulnerable as CDE is not a
          component of these releases.
          
          SCO will make patches and status information available at
          
          http://www.sco.com/security.
          
   Silicon Graphics, Inc.
   
   SGI acknowledges the CDE vulnerabilities reported and is currently
          investigating. No further information is available at this
          time. As further information becomes available, additional
          advisories will be issued via the normal SGI security
          information distribution methods including the wiretap mailing
          list.
          
          Until SGI has more definitive information to provide, customers
          are encouraged to assume all security vulnerabilities as
          exploitable and take appropriate steps according to local site
          security policies and requirements.
          
          The SGI Security Headquarters Web page is accessible at the URL
          
          http://www.sgi.com/Support/security/security.html
          
   Sun Microsystems, Inc.
   
   Vulnerability #1:
          
          Systems running Solaris 7, 2.6, 2.5.1, 2.5, 2.4, and 2.3, and
          SunOS 4.1.4 and 4.1.3_U1 are vulnerable if the UNIX
          authentication mechanism (default) is used with ttsession.
          
          The use of DES authentication is recommended to resolve this
          issue. To set the authentication mechanism to DES, use the
          ttsession command with the '-a' option and specify 'des' as
          the argument (see ttsession(1) for more information). The use
          of DES authentication also requires that the system uses Secure
          NFS, NIS+, or keylogin. For more information about Secure NFS,
          NIS+, or keylogin, please see the System Administration Guide,
          Volume II. Information is also available at:
          
          http://docs.sun.com:80/ab2/coll.47.8/SYSADV2/@Ab2PageView/34908
          ?DwebQuery=secure+rpc
          
          Vulnerability #2:
          
          The following patches are available:
          
    CDE version         SunOS version                   Patch ID
    ___________         _____________                   _________

    1.3                 5.7                             108221-01
    1.3_x86             5.7_x86                         108222-01
    1.2                 5.6                             108199-01
    1.2_x86             5.6_x86                         108200-01
    1.0.2               5.5.1, 5.5, 5.4                 108205-01
    1.0.2_x86           5.5.1_x86, 5.5_x86, 5.4_x86     108206-01
    1.0.1               5.5, 5.4                        108252-01
    1.0.1_x86           5.5_x86, 5.4_x86                108253-01

          Vulnerability #3:
          
          The following patches are available:
          
    CDE version         SunOS version                   Patch ID
    ___________         _____________                   _________

    1.3                 5.7                             108219-01
    1.3_x86             5.7_x86                         108220-01
    1.2                 5.6                             108201-01
    1.2_x86             5.6_x86                         108202-01

          Patches for CDE versions 1.0.2 and 1.0.1 will be available
          within two weeks of the release of this advisory.
          
          Vulnerability #4:
          
          Patches will be available within two weeks of the release of
          this advisory.
          
          Sun security patches are available at:
          
          http://sunsolve.sun.com/pub-cgi/show.pl?target=patches/patch-li
          cense&nav=pubpatches
     _________________________________________________________________
   
   The CERT Coordination Center would like to thank Job de Haas for
   reporting these vulnerabilities and working with the vendors to effect
   fixes. We would also like to thank Network Solutions Atlantic for
   their efforts in coordinating vendor solutions.
   ______________________________________________________________________
   
   This document is available from:
   http://www.cert.org/advisories/CA-99-11-CDE.html
   ______________________________________________________________________
   
CERT/CC Contact Information

   Email: cert@cert.org
          Phone: +1 412-268-7090 (24-hour hotline)
          Fax: +1 412-268-6989
          Postal address:
          CERT Coordination Center
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          Carnegie Mellon University
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          U.S.A.
          
   CERT personnel answer the hotline 08:00-20:00 EST(GMT-5) / EDT(GMT-4)
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   Revision History
   Sep 13, 1999:  Initial release

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