Security Bulletin
Summary
There is a vulnerability in the mount command that affects AIX.
Vulnerability Details
CVEID: CVE-2021-38990
DESCRIPTION: IBM AIX could allow a non-privileged local user to exploit a vulnerability in the mount command which could lead to code execution.
CVSS Base score: 8.4
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/212952 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)
DESCRIPTION: IBM AIX could allow a non-privileged local user to exploit a vulnerability in the mount command which could lead to code execution.
CVSS Base score: 8.4
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/212952 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.rte.filesystem | 7.1.5.0 | 7.1.5.36 |
| bos.rte.filesystem | 7.2.4.0 | 7.2.4.2 |
| bos.rte.filesystem | 7.2.5.0 | 7.2.5.1 |
| bos.rte.filesystem | 7.2.5.100 | 7.2.5.100 |
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.filesystem
Remediation/Fixes
A. APARS
IBM has assigned the following APARs to this problem:
| AIX Level | APAR | SP |
| 7.1.5 | IJ35620 | SP09-2148 |
| 7.2.4 | IJ35826 | SP05 |
| 7.2.5 | IJ35623 | SP03-2147 |
| VIOS Level | APAR | SP |
| 3.1.1 | IJ35826 | 3.1.1.50 |
| 3.1.2 | IJ36125 | 3.1.2.30 |
| 3.1.3 | IJ35623 | 3.1.3.13 |
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 | IJ35620s9a.211130.epkg.Z |
| 7.1.5.8 | IJ35620s9a.211130.epkg.Z |
| 7.1.5.9 | IJ35620s9a.211130.epkg.Z |
| 7.2.4.2 | IJ35826s2a.211130.epkg.Z |
| 7.2.4.3 | IJ35826s4a.211130.epkg.Z |
| 7.2.4.4 | IJ35826s4a.211130.epkg.Z |
| 7.2.5.1 | IJ36125s2a.211130.epkg.Z |
| 7.2.5.2 | IJ36125s2a.211130.epkg.Z |
| 7.2.5.3 | IJ35623s3a.211130.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 |
| 3.1.1.21 | IJ35826s2a.211130.epkg.Z |
| 3.1.1.25 | IJ35826s2a.211130.epkg.Z |
| 3.1.1.30 | IJ35826s4a.211130.epkg.Z |
| 3.1.1.40 | IJ35826s4a.211130.epkg.Z |
| 3.1.2.10 | IJ36125s2a.211130.epkg.Z |
| 3.1.2.21 | IJ36125s2a.211130.epkg.Z |
| 3.1.3.10 | IJ35623s3a.211130.epkg.Z |
To extract the fixes from the tar file:
tar xvf mount_fix.tar
cd mount_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 |
| 08c0bfe458bf5d36a4dfb1841e9b35be6e3c216f38c537d528e16cf2b68239d2 | IJ35620s9a.211130.epkg.Z |
| 52c67adcfdb606dc757bcf40df439fef0dca37bb36e25c3b474fc7f3e80bb93c | IJ35623s3a.211130.epkg.Z |
| 5f7cfdb4181030b7bf42a8512bba399ed67f54203672a42b43dc61813743796f | IJ35826s2a.211130.epkg.Z |
| 178b67c1979a2b9240e727bf737017157ba2a2dd0f3da5568646540efcbaf9b7 | IJ35826s4a.211130.epkg.Z |
| 2ce1eceacfc430e6b37ebdc3a999b77e83b907847978bba15cdcbb31d68897dd | IJ36125s2a.211130.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
Get Notified about Future Security Bulletins
References
Off
Change History
18 May 2022: Fixed typo
06 Jan 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:
18 May 2022
UID
ibm16538700