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

Security Bulletin


Summary

UPDATED Dec 6 (Corrected the affected upper fileset levels for AIX 7.1 TL5 to show that SP10 is affected. Added iFix for 7.1 TL5 SP10) 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)
AIX7.1
AIX7.2
VIOS3.1

 

The vulnerabilities in the following filesets are being addressed:

FilesetLower LevelUpper Level
bos.rte.libc7.1.5.07.1.5.38
bos.rte.libc7.2.3.07.2.3.20
bos.rte.libc7.2.4.07.2.4.3
bos.rte.libc7.2.5.07.2.5.100

 

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 LevelAPARSP
7.1.5IJ35673SP11
7.2.4IJ35675SP05
7.2.5IJ32736SP03-2135

 

VIOS LevelAPARSP
3.1.0IJ35674N/A
3.1.1IJ356753.1.1.50
3.1.2IJ327143.1.2.30

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 LevelInterim Fix
7.1.5.7IJ33560m7b.211112.epkg.Z
7.1.5.8IJ33560m8b.211112.epkg.Z
7.1.5.9IJ35673s9a.211115.epkg.Z
7.1.5.10IJ35673sAa.221206.epkg.Z
7.2.4.2IJ34512m2a.211112.epkg.Z
7.2.4.3IJ34512m3a.211112.epkg.Z
7.2.4.4IJ34512m4a.211112.epkg.Z
7.2.5.1IJ34081m1a.211112.epkg.Z
7.2.5.2IJ34081m2b.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 LevelInterim Fix
3.1.0.40IJ35681m5a.211112.epkg.Z
3.1.0.50IJ35681m6a.211112.epkg.Z
3.1.0.60IJ35681m7a.211112.epkg.Z
3.1.1.21IJ34512m2a.211112.epkg.Z
3.1.1.25IJ34512m2a.211112.epkg.Z
3.1.1.30IJ34512m3a.211112.epkg.Z
3.1.1.40IJ34512m4a.211112.epkg.Z
3.1.2.10IJ34081m1a.211112.epkg.Z
3.1.2.21IJ34081m2b.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 -sha256filename
a997f0597986a2c77789aac9fb256a3e0d513311ef7bd7c7dbdd67ca1ba56ae7IJ33560m7b.211112.epkg.Z
7490cde41556847c89f96b6f079e2287e29ea4e5100db2fd96fe32f0128c24f7IJ33560m8b.211112.epkg.Z
eb592775a18c77a0751678905ac881401aad886471b1c627abceda3bbdec5536IJ34081m1a.211112.epkg.Z
b8f192c3a39508d11142b99ddd881fa73d929d90a8965a952356945d4b1ba31aIJ34081m2b.211112.epkg.Z
b59b364cc0238ecd58a9b2d0b7dd853e58f29fca217a629569c10fe113dc3547IJ34512m2a.211112.epkg.Z
d86f61f1f4d560c16681e98fd07def998e9189a55e59cb2449b5cb38b2d9a66eIJ34512m3a.211112.epkg.Z
4839f55dd72f1a88417e899570104c48154501f2f0d22d03bf2655f29400c8adIJ34512m4a.211112.epkg.Z
b7de872284deb63d440146d39bd9bb77afb6b61f38d63d99c8ee08f5333685c8IJ35673s9a.211115.epkg.Z
31bb35d16b5b0600f54648f1938e690751bf190bd80b9ef8745ebfb44e97f925IJ35673sAa.221206.epkg.Z
846d36d37de4c925a9090de3720eacd53001b3526411e14cdc972b32d43b9b3fIJ35681m5a.211112.epkg.Z
240a051b6fb954a3db28a5269324ad745f9ea86615724aba76615b5ae2112108IJ35681m6a.211112.epkg.Z
b820d632ea6f601f2c748342f9c3f6719b3839aa916b531f3f0a3ea5be424f24IJ35681m7a.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

06 Dec 2022: Corrected the affected upper fileset levels for AIX 7.1 TL5 to show that SP10 is affected. Added iFix for 7.1 TL5 SP10.
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

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:
08 December 2022

UID

ibm16516774