Hash: SHA1

             AUSCERT External Security Bulletin Redistribution

                          ESB-2006.0591 -- [AIX]
         A vulnerability in the setlocale() routine may allow for
                           privilege escalation
                              18 August 2006


        AusCERT Security Bulletin Summary

Product:              bos.rte.libc
Publisher:            IBM
Operating System:     AIX 5.3 and prior
Impact:               Root Compromise
Access:               Existing Account

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Hash: SHA1


First Issued: Thu Aug 17 09:21:47 CDT 2006
                           VULNERABILITY SUMMARY

VULNERABILITY:      A vulnerability in the setlocale() routine may allow
                    for privilege escalation. 

PLATFORMS:          AIX 5.1, 5.2 and 5.3.

SOLUTION:           Apply the APAR, interim fix or workaround as
                    described below.

THREAT:             A local attacker may gain privileges.

CERT VU Number:     n/a
CVE Number:         n/a
                           DETAILED INFORMATION

I.  Description

A security vulnerability was discovered in the setlocale() subroutine.
setlocale() changes or queries a program's entire current locale or
portions thereof. Applications that call setlocale() and that are installed
with the setuid and setgid bit on may be exploited to gain privileges.
setlocale() is exported via libc.a. libc.a is shipped as part of the
bos.rte.libc and bos.adt.prof filesets. Affected versions of these filesets
are listed below.

II. Impact

A local user may gain privileges.

III.  Solutions

A. Official Fix

IBM provides the following fixes:

      APAR number for AIX 5.1.0:  IY88528 (available approx. 09/06/06)
      APAR number for AIX 5.2.0:  IY88512 (available approx. 09/06/06)
      APAR number for AIX 5.3.0:  IY88183 (available approx. 09/06/06)

NOTE: Affected customers are urged to upgrade to the latest applicable
Technology Level.

The following table shows the vulnerable versions of bos.rte.libc and
bos.adt.prof for a given Technology Level.

Technology           Lower         Upper
Level                Level         Level

B. Interim Fix

Interim fixes are available. The ifixes can be downloaded via ftp from:


This is a compressed tarball containing this advisory, interim fix packages
and cleartext PGP signatures for each package.

Verify you have retrieved the fixes intact:
The interim fixes below are named by using the technology level
corresponding to the release that the fix applies to.

The checksums below were generated using the "sum" and "md5sum" commands
and are as follows:

The interim fixes below include prerequisite checking. This will enforce
the correct mapping between the fixes and AIX Technology Levels. The
interim fixes replace libc.a which ships as part of bos.rte.libc. When
installing these fixes, it will be necessary to remove other interim fixes
which modify libc.a.

Filename             sum           md5
5100-07.epkg.Z       00494  3030   a478fdcb09e7785eb6b1f541ad851bc9
5200-07.epkg.Z       56976  3155   2783a81b10c27fbbeed2e3a3adf1deb6
5200-08.epkg.Z       33794  3157   2d96dac2d94acf844b14f71f0148e4d4
5200-09.epkg.Z       00911  3175   7922cac96d0e3d5c7d3da37c842e3681
5300-03.epkg.Z       44064  3525   d347fbae1bfc93c8cc9c9e3c88c5702b
5300-04.epkg.Z       17307  3523   ade47e865f3426a2a0746a3ba2fd81ef
5300-05.epkg.Z       59371  3561   b411b92b6c36df6d163003018cda35fa

These sums should match exactly. The PGP signatures in the compressed
tarball and on this advisory can also be used to verify the integrity of
the various files they correspond to. If the sums or signatures cannot be
confirmed, double check the command results and the download site address.
If those are OK, contact IBM AIX Security at security-alert@austin.ibm.com
and describe the discrepancy.

The following table shows the prerequisite fileset level for the fixes
above. These levels correspond to the latest available versions of
bos.rte.libc for a given technology level.

Filename           Fileset

IMPORTANT: If possible, it is recommended that a mksysb backup of the
system is created. Verify it is both bootable, and readable before

These interim fixes have not been fully regression tested; thus, IBM does
not warrant the fully correct functioning of the interim fix. Customers
install the interim fix and operate the modified version of AIX at their
own risk.

Interim Installation Instructions:

These packages use the new Interim Fix Management Solution to install and
manage ifixes. More information can be found at:


To preview an epkg ifix installation execute the following command:

# emgr -e ipkg_name -p       # where ipkg_name is the name of the
                             # ifix package being previewed.

To install an epkg ifix package, execute the following command:

# emgr -e ipkg_name -X       # where ipkg_name is the name of the
                             # ifix package being installed.

The "X" flag will expand any filesystems if required.

C. Workaround

Remove the setuid and setgid bits from applications that call setlocale().
To determine if an application calls setlocale() use the following command:

dump -T <application> | grep setlocale

IV. Obtaining Fixes

AIX Version 5 APARs can be downloaded from:


Security related Interim Fixes can be downloaded from:


V.  Contact Information

If you would like to receive AIX Security Advisories via email, please


Comments regarding the content of this announcement can be directed to:


To request the PGP public key that can be used to communicate securely
with the AIX Security Team send email to security-alert@austin.ibm.com
with a subject of "get key". The key can also be downloaded from a PGP
Public Key Server. The key id is 0x1B14F299.

Please contact your local IBM AIX support center for any assistance.

eServer is a trademark of International Business Machines Corporation.
IBM, AIX and pSeries are registered trademarks of International Business
Machines Corporation. All other trademarks are property of their respective
Version: GnuPG v1.4.3 (GNU/Linux)


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