AIX /bin/passwd Vulnerability

Original issue date: March 31, 1992
Last revised: September 19, 1997
Attached copyright statement

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

The Computer Emergency Response Team/Coordination Center (CERT/CC) has received information concerning a vulnerability with the passwd command in AIX 3.2 and the 2007 update of AIX 3.1.

IBM is aware of this problem, and a fix is available as apar number "ix23505".  Patches are available for AIX 3.2 and the 2007 update of AIX 3.1.

This fix may be ordered from Level 2 support or by anonymous ftp from ( on the Internet.

  1. To order from IBM call 1-800-237-5511 and ask         that the fix be shipped.  Patches may be obtained         outside the U.S. by contacting your local IBM representative.
  2. If you are on the Internet, use anonymous ftp to obtain the fix from

          Patch           Filename                Checksum
          AIX 3.2         pub/aix3/pas.32.tar.Z   54431  2262
          AIX 3.1 2007    pub/aix3/pas.31.tar.Z   06703    99
    Patches should be retrieved using binary mode.
IBM is currently incorporating the fix into the 3.2 version and 3.1 updates of AIX.  Future shipments of these products should not be vulnerable to this problem.  If you have any questions about products you receive, please contact your IBM representative.

I. Description

The passwd command contains a security vulnerability.

II. Impact

Local users can gain unauthorized root access.

III. Solution

A.  As root, disable /bin/passwd until you obtain and install  the patch.

        # chmod 0500 /bin/passwd

B.  Obtain the fix from IBM and install according to the  directions provided with the patch.

The CERT/CC would like to thank Paul Selick of the University of Toronto for bringing this security vulnerability to our attention.  We would also like to thank IBM for their quick response to this problem, and for making the patches available via anonymous ftp.

This document is available from:

CERT/CC Contact Information

Phone: +1 412-268-7090 (24-hour hotline)
Fax: +1 412-268-6989
Postal address:
CERT Coordination Center
Software Engineering Institute
Carnegie Mellon University
Pittsburgh PA 15213-3890

CERT/CC personnel answer the hotline 08:00-17:00 EST(GMT-5) / EDT(GMT-4) Monday through Friday; they are on call for emergencies during other hours, on U.S. holidays, and on weekends.

Using encryption

We strongly urge you to encrypt sensitive information sent by email.  Our public PGP key is available from

If you prefer to use DES, please call the CERT hotline for more information.

Getting security information

CERT publications and other security information are available from our web site

* "CERT" and "CERT Coordination Center" are registered in the U.S. Patent and Trademark Office.

Any material furnished by Carnegie Mellon University and the Software Engineering Institute is furnished on an "as is" basis. Carnegie Mellon University makes no warranties of any kind, either expressed or implied as to any matter including, but not limited to, warranty of fitness for a particular purpose or merchantability, exclusivity or results obtained from use of the material. Carnegie Mellon University does not make any warranty of any kind with respect to freedom from patent, trademark, or copyright infringement.

Conditions for use, disclaimers, and sponsorship information

Copyright 1992 Carnegie Mellon University.

Revision History
September 19,1997  Attached copyright statement