CERT Vendor Bulletin - HEWLETT-PACKARD SECURITY BULLETIN: #00025

Wed Apr 12 15:59:17 UTC 1995

CERT Vendor-Initiated Bulletin VB-95:03
April 12, 1995

Topic:   Sendmail permits unauthorized remote program execution
Source:  Hewlett-Packard Company
Related CERT documents: CA-95:05 and CA-94:12, "Sendmail Vulnerabilities"

To aid in the wide distribution of essential security information, the CERT
Coordination Center is forwarding the following information from Hewlett-
Packard. HP urges you to act on this information as soon as possible. HP
contact information is included in the forwarded text below; please contact
them if you have any questions or need further information.

========================FORWARDED TEXT STARTS HERE============================

-------------------------------------------------------------------------
      HEWLETT-PACKARD SECURITY BULLETIN: #00025, 2 April 95
-------------------------------------------------------------------------

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.

_______________________________________________________________________
PROBLEM:  Sendmail permits unauthorized remote program execution.
PLATFORM: HP 9000 series 300/400s and 700/800s 8.x and 9.x
DAMAGE:   Remote users can cause sendmail to execute any program.
SOLUTION: Apply patch PHNE_5402 (series 700/800, HP-UX 9.x), or
                      PHNE_5401 (series 700/800, HP-UX 8.x), or
                      PHNE_5384 (series 300/400, HP-UX 9.x), or
                      PHNE_5383 (series 300/400, HP-UX 8.x), or
                      PHNE_5387 (series 700, HP-UX 9.09), or
                      PHNE_5388 (series 700, HP-UX 9.09+), or
                      PHNE_5389 (series 800, HP-UX 9.08)

AVAILABILITY: All patches are available now.
_______________________________________________________________________

I. Vulnerability in /usr/lib/sendmail

   A. A vulnerability in sendmail

   A vulnerability in sendmail has been discovered that permits
   remote users to cause sendmail to execute any program that is
   allowed with the permissions:

        uid=1(daemon) gid=1(other)

   Files and programs that are not world-writeable or world-executable
   and are not in the 'other' group or owned by 'daemon' are
   safe from modification.  This means that /etc/passwd cannot be
   modified, for example.

   B. Fixing the problems

   The two vulnerabilities can be eliminated from releases 8.x and 9.x of
   HP-UX by applying a patch.

   Hewlett-Packard recommends that all customers concerned with the
   security of their HP-UX systems apply the appropriate patch as
   soon as possible.

   It is further advised that system administrators closely scan their
   mail syslogs for evidence of any unusual activity, using:

        grep "|" /usr/spool/mqueue/syslog*

   [Editor's note: If your site links grep to egrep or the Gnu grep,
   the above command matches every line in the file.  An alternative is to
   use fgrep where you are looking for the "|" character. -- CERT CC]

   If there is any evidence of an intrusion, system administrators are
   strongly urged to require password changes for all accounts.

   C. How to Install the Patch (for HP-UX 8.x and 9.x)

   1.  Determine which patch is appropriate for your hardware platform
       and operating system:

         PHNE_5402 (series 700/800, HP-UX 9.x),
         PHNE_5401 (series 700/800, HP-UX 8.x),
         PHNE_5384 (series 300/400, HP-UX 9.x),
         PHNE_5383 (series 300/400, HP-UX 8.x),
         PHNE_5387 (series 700, HP-UX 9.09),
         PHNE_5388 (series 700, HP-UX 9.09+),
         PHNE_5389 (series 800, HP-UX 9.08)

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

        To obtain a copy of the HP SupportLine email service user's guide,
        send the following in the TEXT PORTION OF THE MESSAGE to
        support at support.mayfield.hp.com (no Subject is required):

                      send guide

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

        World Wide Web service for downloading of patches
        is available via our URL:

                http://support.mayfield.hp.com

   3.  Apply the patch to your HP-UX system.

   4.  Examine /tmp/update.log for any relevant WARNINGs or ERRORs.  This
       can be done as follows:

       a.  At the shell prompt, type "tail -60 /tmp/update.log | more"
       b.  Page through the next three screens via the space bar, looking
           for WARNING or ERROR messages.

    D. Impact of the patch and workaround

    The patch for HP-UX releases 8.x and 9.x provides a new version of
    /usr/lib/sendmail which fixes the vulnerability.  No patches will be
    available for versions of HP-UX prior to 8.0.

    E. To subscribe to automatically receive future NEW HP Security
        Bulletins from the HP SupportLine mail service via electronic
        mail, send an email message to:

                  support at support.mayfield.hp.com   (no Subject is required)

        Multiple instructions are allowed in the TEXT PORTION OF THE
        MESSAGE, here are some basic instructions you may want to use:

        To add your name to the subscription list for new security
        bulletins, send the following in the TEXT PORTION OF THE MESSAGE:

                  subscribe security_info

        To retrieve the index of all HP Security Bulletins issued to date,
        send the following in the TEXT PORTION OF THE MESSAGE:

                  send security_info_list

        To get a patch matrix of current HP-UX and BLS security
        patches referenced by either Security Bulletin or Platform/OS,
        put the following in the text portion of your message:

                  send hp-ux_patch_matrix

        World Wide Web service for browsing of bulletins
        is available via our URL:

                http://support.mayfield.hp.com

        Choose "Support news", then under Support news,
        choose "Security Bulletins"

    F. To report new security vulnerabilities, send email to

          security-alert at hp.com

_______________________________________________________________________

=========================FORWARDED TEXT ENDS HERE=============================

CERT bulletins, CERT advisories, information about FIRST representatives, and
other information related to computer security are available for anonymous 
FTP from info.cert.org. 

CERT advisories and bulletins are also posted on the USENET newsgroup
comp.security.announce. If you would like to have future advisories and
bulletins mailed to you or to a mail exploder at your site, please send mail
to cert-advisory-request at cert.org.

If you wish to send sensitive incident or vulnerability information to
CERT staff by electronic mail, we strongly advise that the e-mail be
encrypted.  The CERT Coordination Center can support a shared DES key, PGP
(public key available via anonymous FTP on info.cert.org), or PEM (contact
CERT staff for details).

Internet E-mail: cert at cert.org
Telephone: +1 412-268-7090 (24-hour hotline)
           CERT personnel answer 8:30 a.m.-5:00 p.m. EST(GMT-5)/EDT(GMT-4),
           and are on call for emergencies during other hours.
Fax: +1 412-268-6989

CERT Coordination Center
Software Engineering Institute
Carnegie Mellon University
Pittsburgh, PA 15213-3890
USA

CERT is a service mark of Carnegie Mellon University.