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Security Bulletin: Vulnerabilities in the AIX kernel (CVE-2021-38994, CVE-2021-38995)

Security Bulletin


Summary

There are multiple vulnerabilities in the AIX kernel.

Vulnerability Details

CVEID:   CVE-2021-38995
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/213073 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-2021-38994
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/213072 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)

Affected Products and Versions

Affected Product(s) Version(s)
AIX 7.1
AIX 7.2
AIX 7.3
VIOS 3.1

The vulnerabilities in the following filesets are being addressed:

Fileset Lower Level Upper Level
bos.mp64 7.1.5.0 7.1.5.45
bos.mp64 7.2.4.0 7.2.4.9
bos.mp64 7.2.5.0 7.2.5.3
bos.mp64 7.2.5.100 7.2.5.103
bos.mp64 7.3.0.0 7.3.0.1

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 IJ37452 SP10
7.2.4 IJ37501 SP06
7.2.5 IJ37012 SP04
7.3.0 IJ37001 SP02

VIOS Level APAR SP
3.1.1 IJ37501 3.1.1.60
3.1.2 IJ37776 3.1.2.40
3.1.3 IJ37012 3.1.3.20

Subscribe to the APARs here:
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:
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
7.1.5.7 IJ37452m7a.220215.epkg.Z
7.1.5.8 IJ37452m8a.220215.epkg.Z
7.1.5.9 IJ37452s9a.220215.epkg.Z
7.1.5.9 IJ37452s9b.220215.epkg.Z
7.2.4.3 IJ37501m3a.220215.epkg.Z
7.2.4.4 IJ37501m4a.220215.epkg.Z
7.2.4.5 IJ37501m5a.220215.epkg.Z
7.2.5.1 IJ37776m1a.220215.epkg.Z
7.2.5.2 IJ37776m2a.220215.epkg.Z
7.2.5.3 IJ37012m3a.220215.epkg.Z
7.2.5.3 IJ37012m3b.220215.epkg.Z
7.3.0.1 IJ37001m1a.220215.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 7100-05-09 and 7200-05-03.
IJ37452s9a is for AIX 7100-05-09 with bos.mp64 fileset level 7.1.5.45.
IJ37452s9b is for AIX 7100-05-09 with bos.mp64 fileset level 7.1.5.44.
IJ37012m3a is for AIX 7200-05-03 with bos.mp64 fileset level 7.2.5.103.
IJ37012m3b is for AIX 7200-05-03 with bos.mp64 fileset level 7.2.5.101.
Please reference the Affected Products and Version section above for help with checking installed fileset levels.
VIOS Level Interim Fix
3.1.1.30 IJ37501m3a.220215.epkg.Z
3.1.1.40 IJ37501m4a.220215.epkg.Z
3.1.1.50 IJ37501m5a.220215.epkg.Z
3.1.2.10 IJ37776m1a.220215.epkg.Z
3.1.2.21 IJ37776m2a.220215.epkg.Z
3.1.3.10 IJ37012m3b.220215.epkg.Z
3.1.3.14 IJ37012m3a.220215.epkg.Z
The fixes are cumulative and address previously issued AIX/VIOS kernel security bulletins with respect to SP and TL, which includes:
The fixes for 7.1 TL5 SP7 and SP8 include the following. The fix for 7.1 TL5 SP9 should be installed alongside the following:
https://aix.software.ibm.com/aix/efixes/security/libc_advisory2.asc
https://www.ibm.com/support/pages/node/6516774
To extract the fixes from the tar file:
tar xvf kernel_fix3.tar
cd kernel_fix3
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
10e4ef561cfb0e44a698948eaa3f157c1fbdd22dc6b9095898f813e4e306fa55 IJ37001m1a.220215.epkg.Z
70e53abb9b1b60222a215b04373a79c315d003d5f174f9e1b2fa521bd3201c35 IJ37012m3a.220215.epkg.Z
b575eff5b745fabc369477cec9408e35bfac445d77835ed4df4836ca56fb7cf0 IJ37012m3b.220215.epkg.Z
7c3c4f2aaa7a3624066785211735decfe33bef38c01dff62c3c075f0c4ba535a IJ37452m7a.220215.epkg.Z
328b6d14775423691f5c3b746367e9fdbd24b71230195b93124e2066be499dc4 IJ37452m8a.220215.epkg.Z
6ffa2ad6d1dff2252b4cc5f6e7dfc1a83d15dedc44e0d35f69bfd7b01aab39b8 IJ37452s9a.220215.epkg.Z
e4c7fffdc340a122e42e3a1ce73a6f20ccf0d045dcd4958bc82b69b08add18d8 IJ37452s9b.220215.epkg.Z
ba1c1b1fbe6c1f6a68b6dd48d0f5e61221751d288e8bb141c5e4c2b806322044 IJ37501m3a.220215.epkg.Z
f0dc84ce2145a301b8e7ddbc0e6335bc93fe6468fafb67dd3b67bf73b535c5df IJ37501m4a.220215.epkg.Z
467d4747459d37489b2199d57836de3d79a3837b95c2aa29dc35f43fe33bd0ed IJ37501m5a.220215.epkg.Z
9acb84e45fa3aa0b8d36e9f63d29dcc0e335c0d55351a2a5b8433bd57075dc01 IJ37776m1a.220215.epkg.Z
30e03d25a0657290afb9c04ac1b5b06fd87a8a776dfe037b2d5dd9b92e16c7cd IJ37776m2a.220215.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/ 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:
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:
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

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References

Complete CVSS v3 Guide
On-line Calculator v3

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Related Information

IBM Secure Engineering Web Portal
IBM Product Security Incident Response Blog

AIX Security Bulletin (ASCII format)

Change History

23 Feb 2022: Initial Publication

*The CVSS Environment Score is customer environment specific and will ultimately impact the Overall CVSS Score. Customers can evaluate the impact of this vulnerability in their environments by accessing the links in the Reference section of this Security Bulletin.

Disclaimer

Review the IBM security bulletin disclaimer and definitions regarding your responsibilities for assessing potential impact of security vulnerabilities to your environment.

Document Location

Worldwide

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Document Information

Modified date:
06 April 2022

UID

ibm16558948

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