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IBM SECURITY ADVISORY
 
First Issued: Mon Sep 25 10:00 CDT 2006
==========================================================================
                           VULNERABILITY SUMMARY
 
VULNERABILITY:      An incomplete path vulnerability in the mkvg command
                    may allow a local user in the system group to execute
                    arbitrary commands with root privileges.
 
PLATFORMS:          AIX 5.2 and 5.3.
 
SOLUTION:           Apply the APAR, interim fix or workaround as described
		    below.
 
THREAT:             A local user may execute arbitrary code.
 
CERT VU Number:     n/a
CVE Number:         n/a
==========================================================================
                           DETAILED INFORMATION
 
 
I.  Description
===============
 
A vulnerability was discovered in the mkvg command which may allow a local
user in the system group to execute arbitrary code with root privileges.
extendvg and mkvg are hardlinks to the same executable. These commands are
used to manage volume groups.
 
The mkvg command ships as part of the bos.rte.lvm fileset.
 
To determine if a fileset is installed, execute the following command:
 
# lslpp -L bos.rte.lvm
 
If the fileset is installed, it will be listed along with its version
information, state, type and a description.
 
The following table shows the vulnerable versions of bos.rte.lvm.
 
AIX Release          Lower         Upper
                     Level         Level
===========================================
AIX 5.2              5.2.0.0       5.2.0.95
AIX 5.3              5.3.0.0       5.3.0.51
 
 
II. Impact
==========
 
A local user in the system group may execute arbitrary code with root
privileges.
 
 
III.  Solutions
===============
 
A. APARs
 
IBM provides the following fixes:
 
	APAR number for AIX 5.2.0: IY88722 (available)
	APAR number for AIX 5.3.0: IY88699 (available approx. 10/04/06)
 
NOTE: Affected customers are urged to upgrade to the latest applicable
Technology Level.
 
B. Interim Fix
 
Interim fixes are currently available. The interim fixes can be downloaded
via ftp from:
 
    ftp://aix.software.ibm.com/aix/efixes/security/mkvg_ifix.tar.Z
 
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 APAR corresponding to the
release that the fix applies to. The APAR is followed by an underscore and
the Technology Level for the particular AIX release that a fix applies to.
 
Filename                   sum           md5
=========================================================================
IY88722_07.060908.epkg.Z   05480    19   2ad7419e7f75430396122a01e26efdf5
IY88722_08.060908.epkg.Z   02692    19   e123b6aa85fc172ed34f5772b002317d
IY88722_09.060908.epkg.Z   07748    19   a240624a427b0a81ff1e5855e23c1837
IY88699_03.060824.epkg.Z   50074    22   41b76112f55deeba34a4a8a63c9fc3fb
IY88699_04.060824.epkg.Z   23149    22   65dd39ec02ddc8c9732cfd31a2e4e79e
IY88699_05.060829.epkg.Z   55859    22   07654d6d53bb9801d36c2757ebd6be32
 
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 interim fixes include prerequisite checking. This will ensure the
correct mapping between the interim fixes and AIX Technology Levels. The
following table shows the prerequisite fileset levels required for the
fixes above. The fileset levels listed are for bos.rte.lvm.
 
Interim                    Fileset Level     Fileset Level
Fix                        (lower limit)     (upper limit)
===================================================================
IY88722_07.060908.epkg.Z   5.2.0.77	     5.2.0.79
IY88722_08.060908.epkg.Z   5.2.0.86	     5.2.0.88
IY88722_09.060908.epkg.Z   5.2.0.95	     5.2.0.95
IY88699_03.060824.epkg.Z   5.3.0.32	     5.3.0.32
IY88699_04.060824.epkg.Z   5.3.0.44	     5.3.0.44
IY88699_05.060829.epkg.Z   5.3.0.50	     5.3.0.51
 
IMPORTANT: If possible, it is recommended that a mksysb backup of the
system is created. Verify it is both bootable, and readable before
proceeding.
 
Customers may contact IBM support if any issues arise with these interim
fixes.
 
Interim Installation Instructions:
+---------------------------------
 
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.
 
C. Workaround
 
Remove the setuid bit. Note that this may prevent the mkvg and extendvg
commands for functioning normally for non-root users. This can be done by
executing the following command:
 
# chmod 550 /usr/sbin/mkvg
 
Verify the changes:
 
# ls -la /usr/sbin/mkvg
- -r-xr-x---   2 root     system        26314 Mar  5 2005  /usr/sbin/mkvg
 
 
IV. 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
 
 
V.  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 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
holders.
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