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Security Bulletin: Vulnerability in libc affects AIX (CVE-2021-29860)

Security Bulletin


Summary

There is a vulnerability in the libc.a library that affects AIX.

Vulnerability Details

CVEID:   CVE-2021-29860
DESCRIPTION:   IBM AIX could allow a non-privileged local user to exploit a vulnerability in the libc.a library to expose sensitive information.
CVSS Base score: 6.2
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/206084 for the current score.
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N)

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.rte.libc 7.1.5.0 7.1.5.37
bos.rte.libc 7.2.3.0 7.2.3.20
bos.rte.libc 7.2.4.0 7.2.4.3
bos.rte.libc 7.2.5.0 7.2.5.2

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.rte.libc

Remediation/Fixes

A. APARS
IBM has assigned the following APARs to this problem:
AIX Level APAR SP
7.1.5 IJ35673 SP10
7.2.4 IJ35675 SP05
7.2.5 IJ32736 SP03-2135

VIOS Level APAR SP
3.1.0 IJ35674 N/A
3.1.1 IJ35675 3.1.1.50
3.1.2 IJ32714 3.1.2.30

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 IJ33560m7b.211112.epkg.Z
7.1.5.8 IJ33560m8b.211112.epkg.Z
7.1.5.9 IJ35673s9a.211115.epkg.Z
7.2.4.2 IJ34512m2a.211112.epkg.Z
7.2.4.3 IJ34512m3a.211112.epkg.Z
7.2.4.4 IJ34512m4a.211112.epkg.Z
7.2.5.1 IJ34081m1a.211112.epkg.Z
7.2.5.2 IJ34081m2b.211112.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.
Please reference the Affected Products and Version section above for help with checking installed fileset levels.
VIOS Level Interim Fix
3.1.0.40 IJ35681m5a.211112.epkg.Z
3.1.0.50 IJ35681m6a.211112.epkg.Z
3.1.0.60 IJ35681m7a.211112.epkg.Z
3.1.1.21 IJ34512m2a.211112.epkg.Z
3.1.1.25 IJ34512m2a.211112.epkg.Z
3.1.1.30 IJ34512m3a.211112.epkg.Z
3.1.1.40 IJ34512m4a.211112.epkg.Z
3.1.2.10 IJ34081m1a.211112.epkg.Z
3.1.2.21 IJ34081m2b.211112.epkg.Z
To extract the fixes from the tar file:
tar xvf libc_fix2.tar
cd libc_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
a997f0597986a2c77789aac9fb256a3e0d513311ef7bd7c7dbdd67ca1ba56ae7 IJ33560m7b.211112.epkg.Z
7490cde41556847c89f96b6f079e2287e29ea4e5100db2fd96fe32f0128c24f7 IJ33560m8b.211112.epkg.Z
eb592775a18c77a0751678905ac881401aad886471b1c627abceda3bbdec5536 IJ34081m1a.211112.epkg.Z
b8f192c3a39508d11142b99ddd881fa73d929d90a8965a952356945d4b1ba31a IJ34081m2b.211112.epkg.Z
b59b364cc0238ecd58a9b2d0b7dd853e58f29fca217a629569c10fe113dc3547 IJ34512m2a.211112.epkg.Z
d86f61f1f4d560c16681e98fd07def998e9189a55e59cb2449b5cb38b2d9a66e IJ34512m3a.211112.epkg.Z
4839f55dd72f1a88417e899570104c48154501f2f0d22d03bf2655f29400c8ad IJ34512m4a.211112.epkg.Z
b7de872284deb63d440146d39bd9bb77afb6b61f38d63d99c8ee08f5333685c8 IJ35673s9a.211115.epkg.Z
846d36d37de4c925a9090de3720eacd53001b3526411e14cdc972b32d43b9b3f IJ35681m5a.211112.epkg.Z
240a051b6fb954a3db28a5269324ad745f9ea86615724aba76615b5ae2112108 IJ35681m6a.211112.epkg.Z
b820d632ea6f601f2c748342f9c3f6719b3839aa916b531f3f0a3ea5be424f24 IJ35681m7a.211112.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

Get Notified about Future Security Bulletins

References

Off

Acknowledgement

Change History

16 Nov 2021: 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

According to the Forum of Incident Response and Security Teams (FIRST), the Common Vulnerability Scoring System (CVSS) is an "industry open standard designed to convey vulnerability severity and help to determine urgency and priority of response." IBM PROVIDES THE CVSS SCORES ""AS IS"" WITHOUT WARRANTY OF ANY KIND, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. CUSTOMERS ARE RESPONSIBLE FOR ASSESSING THE IMPACT OF ANY ACTUAL OR POTENTIAL SECURITY VULNERABILITY.

Document Location

Worldwide

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Document Information

Modified date:
16 December 2021

UID

ibm16516774