Headline
CVE-2021-38955: Security Bulletin: Vulnerability in AIX audit commands (CVE-2021-38955)
IBM AIX 7.1, 7.2, 7.3, and VIOS 3.1 could allow a local user with elevated privileges to cause a denial of service due to a file creation vulnerability in the audit commands. IBM X-Force ID: 211825.
Security Bulletin
Summary
There is a vulnerability in the AIX audit user commands.
Vulnerability Details
CVEID: CVE-2021-38955
DESCRIPTION: IBM AIX could allow a local user with elevated privileges to cause a denial of service due to a file creation vulnerability in the audit commands.
CVSS Base score: 4.4
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/211825 for the current score.
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:H/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.rte.security
7.1.5.0
7.1.5.37
bos.rte.security
7.2.4.0
7.2.4.4
bos.rte.security
7.2.5.0
7.2.5.2
bos.rte.security
7.2.5.100
7.2.5.101
bos.rte.security
7.3.0.0
7.3.0.0
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.security
Remediation/Fixes
A. APARS
IBM has assigned the following APARs to this problem:
AIX Level
APAR
SP
7.1.5
IJ38113
SP10
7.2.4
IJ38115
SP06
7.2.5
IJ38117
SP04
7.3.0
IJ38121
SP02
VIOS Level
APAR
SP
3.1.1
IJ38115
3.1.1.60
3.1.2
IJ38119
3.1.2.40
3.1.3
IJ38117
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.
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
IJ38113m9a.220227.epkg.Z
7.1.5.8
IJ38113m9a.220227.epkg.Z
7.1.5.9
IJ38113m9a.220227.epkg.Z
7.2.4.3
IJ38115m5a.220227.epkg.Z
7.2.4.4
IJ38115m5a.220227.epkg.Z
7.2.4.5
IJ38115m5a.220227.epkg.Z
7.2.5.1
IJ38119m2a.220227.epkg.Z
7.2.5.2
IJ38119m2a.220227.epkg.Z
7.2.5.3
IJ38117m3a.220227.epkg.Z
7.3.0.1
IJ38121m1a.220227.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
3.1.1.30
IJ38115m5a.220227.epkg.Z
3.1.1.40
IJ38115m5a.220227.epkg.Z
3.1.1.50
IJ38115m5a.220227.epkg.Z
3.1.2.10
IJ38119m2a.220227.epkg.Z
3.1.2.21
IJ38119m2a.220227.epkg.Z
3.1.3.10
IJ38117m3a.220227.epkg.Z
3.1.3.14
IJ38117m3a.220227.epkg.Z
To extract the fixes from the tar file:
tar xvf audit_fix.tar
cd audit_fix
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
9c106a0fcc85c04f1cb41b939b3019daa7fb2fa2b826f6ea41bf4b6e415f54ae
IJ38113m9a.220227.epkg.Z
3da452a1fadea25122c899a851907b8df6e0346f016373e22e98a36a7deedaf2
IJ38115m5a.220227.epkg.Z
abcc517295ba08a79f994f1091778c7845729cb96a0ac5530b0777ea23e93050
IJ38117m3a.220227.epkg.Z
851e4b2c602e5e869b36bea8190da813b880f10aae6227f2595ecf06289dd58c
IJ38119m2a.220227.epkg.Z
e61fce4c31be526987ad5842155d71a8912622dde0b76091545ad3a40ea70f78
IJ38121m1a.220227.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
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
References
Off
Change History
28 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
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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