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AUSCERT External Security Bulletin Redistribution
ESB-2007.0570 -- [AIX]
AIX pioout Arbitrary Library Loading Vulnerability
27 July 2007
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AusCERT Security Bulletin Summary
---------------------------------
Product: pioout(4)
Publisher: IBM
Operating System: AIX 5.2, 5.3
Impact: Root Compromise
Access: Existing Account
CVE Names: CVE-2007-4003
Original Bulletin:
http://labs.idefense.com/intelligence/vulnerabilities/display.php?id=569
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IBM SECURITY ADVISORY
First Issued: Thu Jul 19 16:51:01 CDT 2007
===============================================================================
VULNERABILITY SUMMARY
VULNERABILITY: AIX pioout Arbitrary Library Loading Vulnerability
PLATFORMS: AIX 5.2, 5.3
SOLUTION: Apply the APAR, interim fix or workaround as described
below.
THREAT: An attacker may run arbitrary code with root privileges.
CERT VU Number: n/a
CVE Number: n/a
===============================================================================
DETAILED INFORMATION
I. OVERVIEW
The pioout command is at the end of pipelines invoked by the piobe command
(the print job manager) to print a file or a burst page on a printer.
II. DESCRIPTION
An arbitrary library loading vulnerability exists within the pioout command
which allows a non-privileged user to execute arbitrary code with super-
user privileges. This vulnerability is the result of pioout being setuid
and world executable.
III. IMPACT
Successful exploitation of this vulnerability will allow a local user to
run arbitrary code with root privileges.
IV. PLATFORM VULNERABILITY ASSESSMENT
To determine if your system is vulnerable, run the following command:
# lslpp -l | grep printers.rte
The following filesets are vulnerable:
AIX Level Lower Level Upper Level
-------------------------------------------------
5.2.0 5.2.0.75 5.2.0.105
5.3.0 5.3.0.30 5.3.0.60
V. SOLUTIONS
A. APARS
IBM provides the following fixes:
AIX Level APAR number Availability
--------------------------------------------------------------------
5.2.0 IZ01121 10/31/2007 (subject to change)
5.3.0 IZ01122 08/08/2007 (subject to change)
AIX Version 5 APARs can be downloaded from:
http://www.ibm.com/servers/eserver/support/unixservers/aixfixes.html
NOTE: Affected customers are urged to upgrade to the latest applicable
Technology Level and Service Pack.
B. INTERIM FIXES
Interim fixes are available. The interim fix can be downloaded via
ftp from:
ftp://aix.software.ibm.com/aix/efixes/security/pioout_ifix.tar.Z
This is a compressed tarball containing this advisory, interim fix
packages and PGP signatures for each package. The interim fixes below
include prerequisite checking. This will enforce the correct mapping
between the fixes and AIX Technology Levels.
AIX Release & Technology Level Interim fix
---------------------------------------------------------------
5200-08 IZ01121_08.070719.epkg.Z
5200-09 IZ01121_09.070719.epkg.Z
5200-10 IZ01121_10.070719.epkg.Z
5300-04 IZ01122_04.070719.epkg.Z
5300-05 IZ01122_05.070719.epkg.Z
5300-06 IZ01122_06.070719.epkg.Z
IMPORTANT: If possible, it is recommended that a mksysb backup of the
system be created. Verify it is both bootable and readable before
proceeding.
These interim fixes have not been fully regression tested; thus, IBM
does not warrant the fully correct functionality of the interim fix.
Customers install the interim fix and operate the modified version of
AIX at their own risk.
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:
Filename sum md5sum
----------------------------------------------------------------------
IZ01121_08.070710.epkg.Z 50647 45 a821b7be0890066ebb7e08370c2431bb
IZ01121_09.070710.epkg.Z 15247 45 e38cb8dcd2e46b2a0d260beac059f075
IZ01121_10.070710.epkg.Z 43854 45 fe45e6967d616b829b26452def22dd20
IZ01122_04.070710.epkg.Z 14449 45 3da46671ac956c0ec341da0f6ea56ea6
IZ01122_05.070710.epkg.Z 10193 45 878460aa65e0446d692e6d9585475c9a
IZ01122_06.070710.epkg.Z 29050 46 3f14967bcb2deeb3fc9a34fbd21ea52d
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.
C. INTERIM FIX INSTALLATION
These packages use the new Interim Fix Management Solution to install
and manage interim fixes. More information can be found at:
http://www14.software.ibm.com/webapp/set2/sas/f/aix.efixmgmt/home.html
To preview an epkg interim fix installation execute the following
command:
# emgr -e ipkg_name -p # where ipkg_name is the name of the
# interim fix package being previewed.
To install an epkg interim fix package, execute the following command:
# emgr -e ipkg_name -X # where ipkg_name is the name of the
# interim fix package being installed.
The "X" flag will expand any filesystems if required.
VI. WORKAROUNDS
A. OPTION 1
In most cases the pioout command will only be run by a privileged user
and can have its permissions altered with the following command:
# chmod 500 /usr/lib/lpd/pio/etc/pioout
NOTE: This will affect users of the printq group attempting to run this
command.
B. OPTION 2
Customers running AIX 5.3.0 TL06 may install the bos.rte.security
fileset and take advantage of the 'fpm' command to disable the setuid
capabilities of pioout. The pioout command is part of the 'high' level
database.
VII. OBTAINING FIXES
AIX Version 5 APARs can be downloaded from:
http://www.ibm.com/servers/eserver/support/unixservers/aixfixes.html
Security related Interim Fixes can be downloaded from:
ftp://aix.software.ibm.com/aix/efixes/security
VII. CONTACT INFORMATION
If you would like to receive AIX Security Advisories via email, please
visit:
http://www14.software.ibm.com/webapp/set2/subscriptions/pqvcmjd
Comments regarding the content of this announcement can be directed to:
security-alert@austin.ibm.com
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
0x4265D862.
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 holders.
VIII. ACKNOWLEDGMENTS
iDefense (http://labs.idefense.com/) credits an anonymous contributer.
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