SB50 Security vulnerability in the chsh executable

SB50 Security vulnerability in the chsh executable

Post by Security Ale » Sat, 11 Jan 1997 04:00:00



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       HEWLETT-PACKARD SECURITY BULLETIN: #00050, 09 January 1997
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The information in the following Security Bulletin should be acted upon
as soon as possible.  Hewlett Packard will not be liable for any
consequences to any customer resulting from customer's failure to fully
implement instructions in this Security Bulletin as soon as possible.

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PROBLEM:  Security vulnerability in the chsh executable

PLATFORM: HP 9000 Series 700/800s running versions of HP-UX 9.X & 10.X

DAMAGE:   Vulnerabilities exists allowing local users to gain root
          privileges.

SOLUTION: Apply patch:
          PHCO_9600 for all platforms with HP-UX releases 9.X
          PHCO_9601 for all platforms with HP-UX releases 10.00/10.01/10.10
          PHCO_9602 for all platforms with HP-UX releases 10.20

AVAILABILITY:  All patches are available now.

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I.
   A. Background
      A vulnerability with the chsh command (/usr/bin/chsh) has been
      discovered.

   B. Fixing the problem
      The vulnerability can be eliminated from HP-UX releases 9.X and
      10.X by applying the appropriate patch.

        NOTE:  The patch fixes /usr/bin/chsh.  Once installed, it is
               necessary to also replace the file /bin/chsh file, which
               placed there to be backwards compatible.

   C. Recommended solution
      1.  Determine which patch are appropriate for your operating
          system.

      2.  Hewlett-Packard's HP-UX patches are available via email
          and the World Wide Web

          To obtain a copy of the Hewlett-Packard SupportLine email
          service user's guide, send the following in the TEXT PORTION

          is required):

                               send guide

          The users guide explains the HP-UX patch downloading process
          via email and other services available.

          World Wide Web service for downloading of patches
          is available via our URL:
                  (http://us.external.hp.com)
      3.  Apply the patch to your HP-UX system.

        NOTE:  The patch fixes /usr/bin/chsh.  Once installed, it is
               necessary to also replace the file /bin/chsh file, which
               placed there to be backwards compatible.

      4.  Examine /tmp/update.log (9.X), or /var/adm/sw/swinstall.log
          (10.X), for any relevant WARNING's or ERROR's.

   D. Impact of the patch
      The patches for HP-UX releases 9.X and 10.X provide enhancements
      to the chsh executable to avoid this vulnerability.

   E. To subscribe to automatically receive future NEW HP Security
      Bulletins from the HP SupportLine Digest service via electronic
      mail, do the following:

      1)  From your Web browser, access the URL:

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

      http://europe-support.external.hp.com  (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    

   F. To report new security vulnerabilities, send email to


      Please encrypt any exploit information using the security-alert
      PGP key, available from your local key server, or by sending a
      message with a -subject- (not body) of 'get key' (no quotes) to

   Permission is granted for copying and circulating this Bulletin to
   Hewlett-Packard (HP) customers (or the Internet community) for the
   purpose of alerting them to problems, if and only if, the Bulletin is
   not edited or changed in any way, is attributed to HP, and provided
   such reproduction and/or distribution is performed for non-commercial
   purposes.

   Any other use of this information is prohibited.  HP is not liable
   for any misuse of this information by any third party.
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