Summary

There are multiple vulnerabilities in the AIX kernel.

Update 2: Wed Sep 1 16:11:34 CDT 2021
Update: Additional iFixes are now available.
Additional iFixes are now available for:
AIX 7100-05-06 and 7100-05-07
AIX 7200-03-05 and 7200-03-06
AIX 7200-04-02 and 7200-04-03
AIX 7200-05-01
VIOS 3.1.0.40 and 3.1.0.50
VIOS 3.1.1.25 and 3.1.1.30
VIOS 3.1.2.10
Updated: Fri Aug 27 08:31:32 CDT 2021
Update: Corrected the AIX 7.1 TL5 affected fileset levels. The upper affected fileset level for AIX 7.1 TL5 is bos.mp64 7.1.5.42.

Vulnerability Details

CVEID:CVE-2021-29862
**DESCRIPTION:**IBM AIX could allow a non-privileged local user to exploit a vulnerability in the AIX kernel to cause a denial of service.
CVSS Base score: 6.2
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/206086 for the current score.
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

CVEID:CVE-2021-29727
**DESCRIPTION:**IBM AIX could allow a local user to exploit a vulnerability in the AIX kernel to cause a denial of service.
CVSS Base score: 6.2
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/201106 for the current score.
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

CVEID:CVE-2021-29801
**DESCRIPTION:**IBM AIX could allow a non-privileged local user to exploit a vulnerability in the kernel to gain root privileges.
CVSS Base score: 8.4
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/203977 for the current score.
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H)

Affected Products and Versions

Affected Product(s)	Version(s)
AIX	7.1
AIX	7.2
VIOS	3.1

The vulnerabilities in the following filesets are being addressed:

Fileset	Lower Level	Upper Level
bos.mp64	7.1.5.0	7.1.5.42
bos.mp64	7.2.3.0	7.2.3.21
bos.mp64	7.2.4.0	7.2.4.8
bos.mp64	7.2.5.0	7.2.5.3

To find out whether the affected filesets are installed on your systems, refer to the lslpp command found in AIX user’s guide.

Example: lslpp -L | grep -i bos.mp64

Remediation/Fixes

A. APARS

IBM has assigned the following APARs to this problem:

AIX Level	APAR	SP
7.1.5	IJ33318	SP09
7.2.3	IJ32629	N/A
7.2.4	IJ32630	SP05
7.2.5	IJ32415	SP03

VIOS Level	APAR	SP
3.1.0	IJ32629	N/A
3.1.1	IJ32630	3.1.1.50
3.1.2	IJ32631	3.1.2.30

Subscribe to the APARs here:

<https://www.ibm.com/support/pages/apar/IJ33318&gt;

<https://www.ibm.com/support/pages/apar/IJ32629&gt;

<https://www.ibm.com/support/pages/apar/IJ32630&gt;

<https://www.ibm.com/support/pages/apar/IJ32631&gt;

By subscribing, you will receive periodic email alerting you to the status of the APAR, and a link to download the fix once it becomes available.

B. FIXES

AIX and VIOS fixes are available.

An LPAR system reboot is required to complete the iFix installation, or Live Update may be used on AIX 7.2 to avoid a reboot.

The AIX and VIOS fixes can be downloaded via ftp or http from:

ftp://aix.software.ibm.com/aix/efixes/security/kernel_fix2.tar

<http://aix.software.ibm.com/aix/efixes/security/kernel_fix2.tar&gt;

<https://aix.software.ibm.com/aix/efixes/security/kernel_fix2.tar&gt;

The link above is to a tar file containing this signed advisory, fix packages, and OpenSSL signatures for each package. The fixes below include prerequisite checking. This will enforce the correct mapping between the fixes and AIX Technology Levels.

AIX Level	Interim Fix
7.1.5.6	IJ33318m6a.210816.epkg.Z
7.1.5.7	IJ33318m7a.210813.epkg.Z
7.1.5.8	IJ33318m8a.210813.epkg.Z
7.2.3.5	IJ32629m5a.210805.epkg.Z
7.2.3.6	IJ32629m6a.210805.epkg.Z
7.2.3.7	IJ32629s7a.210805.epkg.Z
7.2.4.2	IJ32630m2e.210901.epkg.Z
7.2.4.2	IJ32630m2f.210901.epkg.Z
7.2.4.3	IJ32630m3b.210901.epkg.Z
7.2.4.4	IJ32630s4a.210813.epkg.Z
7.2.5.1	IJ32631m1a.210805.epkg.Z
7.2.5.2	IJ32631s2a.210805.epkg.Z

Please note that the above table refers to AIX TL/SP level as opposed to fileset level, i.e., 7.2.5.2 is AIX 7200-05-02.

NOTE: Multiple iFixes are provided for AIX 7200-04-02.
IJ32630m2e is for AIX 7200-04-02 with bos.mp64 fileset level 7.2.4.6.
IJ32630m2f is for AIX 7200-04-02 with bos.mp64 fileset level 7.2.4.4.

Please reference the Affected Products and Version section above for help with checking installed fileset levels.

VIOS Level	Interim Fix
3.1.0.40	IJ32629m5a.210805.epkg.Z
3.1.0.50	IJ32629m6a.210805.epkg.Z
3.1.0.60	IJ32629s7a.210805.epkg.Z
3.1.1.21	IJ32630m2f.210901.epkg.Z
3.1.1.25	IJ32630m2e.210901.epkg.Z
3.1.1.30	IJ32630m3b.210901.epkg.Z
3.1.1.40	IJ32630s4a.210813.epkg.Z
3.1.2.10	IJ32631m1a.210805.epkg.Z
3.1.2.21	IJ32631s2a.210805.epkg.Z

The fixes are cumulative and address previously issued AIX/VIOS kernel security bulletins with respect to SP and TL, which includes:

<https://aix.software.ibm.com/aix/efixes/security/trace_advisory.asc&gt;

<https://www.ibm.com/support/pages/node/6464369&gt;

<https://aix.software.ibm.com/aix/efixes/security/gencore_advisory.asc&gt;

<https://www.ibm.com/support/pages/node/6406022&gt;

<https://aix.software.ibm.com/aix/efixes/security/power9_advisory.asc&gt;

<https://www.ibm.com/support/pages/node/6370729&gt;

To extract the fixes from the tar file:

tar xvf kernel_fix2.tar

cd kernel_fix2

Verify you have retrieved the fixes intact:

The checksums below were generated using the “openssl dgst -sha256 [filename]” command as the following:

openssl dgst -sha256	filename
dccf7e96800c47b042d707aa27cf9a02c5ede3ed0de9f9c264d1438bb37a9a03	IJ32629m5a.210805.epkg.Z
45304b30684c3ba59a1106cc70ad1fcb0542cc5108bfc97ace4826ab34f8d7ad	IJ32629m6a.210805.epkg.Z
9dee72202fc0211874b76660e3571c3ff6ffbe811682903af9e95038a47d0552	IJ32629s7a.210805.epkg.Z
900ffced3671f25b60351e7fd7bee8282d66a89abd6826ae9d1aa5bb295f8452	IJ32630m2e.210901.epkg.Z
579d8d5d6c5550dc410b9b189bdaaa5d356a435e1466d69add10c992065da611	IJ32630m2f.210901.epkg.Z
4c23de46e121caddec42ef4c5f98d3a058c749d7624305dde817ec45874040cc	IJ32630m3b.210901.epkg.Z
5c24ca516cc0e14a297020473b5311deaff56a7eb3519ee887d3a4accc719c20	IJ32630s4a.210813.epkg.Z
191c759367ddf5c4b7318eb4171fe222194e6b88f78f6abede81de6370761522	IJ32631m1a.210805.epkg.Z
bbaef236cc66ff140ac2301ec59fffea003570efeb764ac44db3101c394b6838	IJ32631s2a.210805.epkg.Z
af04022a969f8f0415be13c74524e6112e985686456d1565502af2e68230364b	IJ33318m6a.210816.epkg.Z
0f183f42aad6720559a1efa7e1de8534a9889fc1cc8c1cc4b8e03ebf9bbf146a	IJ33318m7a.210813.epkg.Z
e0e80a9ca47382f11d0d9cde04fe305492cf4c5c772f345a1413013de5095446	IJ33318m8a.210813.epkg.Z

These sums should match exactly. The OpenSSL signatures in the tar file and on this advisory can also be used to verify the integrity of the fixes. If the sums or signatures cannot be confirmed, contact IBM Support at <http://ibm.com/support/&gt; and describe the discrepancy.

openssl dgst -sha256 -verify [pubkey_file] -signature [advisory_file].sig [advisory_file]

openssl dgst -sha256 -verify [pubkey_file] -signature [ifix_file].sig [ifix_file]

Published advisory OpenSSL signature file location:

<http://aix.software.ibm.com/aix/efixes/security/kernel_advisory2.asc.sig&gt;

<https://aix.software.ibm.com/aix/efixes/security/kernel_advisory2.asc.sig&gt;

ftp://aix.software.ibm.com/aix/efixes/security/kernel_advisory2.asc.sig

C. FIX AND INTERIM FIX INSTALLATION

An LPAR system reboot is required to complete the iFix installation, or Live Update may be used on AIX 7.2 to avoid a reboot.

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

To preview a fix installation:

installp -a -d fix_name -p all # where fix_name is the name of the

fix package being previewed.

To install a fix package:

installp -a -d fix_name -X all # where fix_name is the name of the

fix package being installed.

Interim fixes have had limited functional and regression testing but not the full regression testing that takes place for Service Packs; however, IBM does fully support them.

Interim fix management documentation can be found at:

<http://www14.software.ibm.com/webapp/set2/sas/f/aix.efixmgmt/home.html&gt;

To preview an interim fix installation:

emgr -e ipkg_name -p # where ipkg_name is the name of the

interim fix package being previewed.

To install an interim fix package:

emgr -e ipkg_name -X # where ipkg_name is the name of the

interim fix package being installed.

Workarounds and Mitigations

None