CERT Advisory - Revised Hewlett-Packard NIS ypbind Vulnerability

CERT Advisory cert-advisory-request at cert.org
Wed Jan 13 20:22:42 UTC 1993

CA-93:01                         CERT Advisory
                               January 13, 1993
                Revised Hewlett-Packard NIS ypbind Vulnerability


                   *** THIS IS A REVISED CERT ADVISORY ***
                  *** SUPERSEDES CERT ADVISORY CA-92:17 ***

The CERT Coordination Center has received information concerning a
vulnerability in the NIS ypbind module for the Hewlett-Packard (HP)
HP/UX Operating System for series 300, 700, and 800 computers. 

HP has provided revised patches for all of the HP/UX level 8 releases
(8.0, 8.02, 8.06, and 8.07).  This problem is fixed in HP/UX 9.0.
The following patches have been superseded:

              Patch ID        Replaced by Patch ID
              PHNE_1359       PHNE_1706
              PHNE_1360       PHNE_1707
              PHNE_1361       PHNE_1708

All HP NIS clients and servers running ypbind should obtain and 
install the patch appropriate for their machine's architecture
as described below.


I.   Description

     A vulnerability in HP NIS allows unauthorized access to NIS data.

II.  Impact

     Root on a remote host running any vendor's implementation of NIS
     can gain root access on any local host running HP's NIS ypbind. 
     Local users of a host running HP's NIS ypbind can also gain root access.

III. Solution
     1) All HP NIS clients and servers running ypbind should obtain and 
        install the patch appropriate for their machine's architecture.

        These patches contain a version of ypbind that only accepts ypset
        requests from a superuser port on the local host.  This prevents
        a non-superuser program from sending rogue ypset requests to ypbind.
        They also include the mod from the superseded patches which prevented
        a superuser on a remote system from issuing a ypset -h command
        to the local system and binding the system to a rogue ypserver.

        These patches may be obtained from HP via FTP (this is NOT
        anonymous FTP) or the HP SupportLine.  To obtain HP security
        patches, you must first register with the HP SupportLine.
        The registration instructions are available via
	anonymous FTP at cert.org ( in the file
        The new patch files are:

     Architecture Patch ID   Filename                               Checksum
     ------------ --------   --------                               --------
     Series 300   PHNE_1706  /hp-ux_patches/s300_400/8.X/PHNE_1706  38955 212
     Series 700   PHNE_1707  /hp-ux_patches/s700/8.X/PHNE_1707        815 311
     Series 800   PHNE_1708  /hp-ux_patches/s800/8.X/PHNE_1708      56971 299

     2) The instructions for installing the patch are provided in the
        PHNE_xxxx.text file (this file is created after the patch has
        been unpacked).

        The checksums listed above are for the patch archive files from HP.
        Once unpacked, each shell archive contains additional checksum 
        information in the file "patchfilename.text".  This checksum is
        applicable to the binary patch file "patchfilename.updt".

If you have any questions about obtaining or installing the patches,
contact the USA HP SupportLine at 415-691-3888, or your local HP
SupportLine number.  Please note that the telephone numbers in this
advisory are appropriate for the USA and Canada. 

The CERT Coordination Center wishes to thank Brian Kelley of Ford Motor
Company for bringing this vulnerability to our attention.  We would also
like to thank Hewlett-Packard for their response to this problem. 

If you believe that your system has been compromised, contact the CERT
Coordination Center or your representative in FIRST (Forum of Incident
Response and Security Teams).

Internet E-mail: cert at cert.org
Telephone: 412-268-7090 (24-hour hotline)
           CERT personnel answer 7:30 a.m.-6:00 p.m. EST(GMT-5)/EDT(GMT-4),
           on call for emergencies during other hours.

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

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

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