CentOS ProjectKSH_ADVISORY.ASCThere is a vulnerability in Korn Shell (ksh) that affects AIX,There is a vulnerability in Korn Shell (ksh) that affects VIOS
7.2 High
CVSS2
Attack Vector
LOCAL
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
COMPLETE
Integrity Impact
COMPLETE
Availability Impact
COMPLETE
AV:L/AC:L/Au:N/C:C/I:C/A:C
7.8 High
CVSS3
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
0.0004 Low
EPSS
Percentile
5.1%
IBM SECURITY ADVISORY
First Issued: Fri Jul 30 14:43:36 CDT 2021
|Updated: Wed Aug 11 14:52:54 CDT 2021
|Update: Corrected the AIX 7.1 TL5 affected fileset levels.
The most recent version of this document is available here:
http://aix.software.ibm.com/aix/efixes/security/ksh_advisory.asc
https://aix.software.ibm.com/aix/efixes/security/ksh_advisory.asc
ftp://aix.software.ibm.com/aix/efixes/security/ksh_advisory.asc
Security Bulletin: Vulnerability in ksh affects AIX (CVE-2021-29741)
===============================================================================
SUMMARY:
There is a vulnerability in Korn Shell (ksh) that affects AIX.
===============================================================================
VULNERABILITY DETAILS:
CVEID: CVE-2021-29741
https://vulners.com/cve/CVE-2021-29741
https://vulners.com/cve/CVE-2021-29741
DESCRIPTION: IBM AIX could allow a local user to exploit a vulnerability
in Korn Shell (ksh) to gain root privileges.
CVSS Base Score: 8.4
CVSS Temporal Score: See
https://exchange.xforce.ibmcloud.com/vulnerabilities/201478
for the current score
CVSS Environmental Score*: Undefined
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:
AIX 7.1, 7.2
VIOS 3.1
The vulnerabilities in the following filesets are being addressed:
key_fileset = aix
Fileset Lower Level Upper Level KEY
---------------------------------------------------------
| bos.rte.shell 7.1.5.30 7.1.5.36 key_w_fs
bos.rte.shell 7.2.3.0 7.2.3.20 key_w_fs
bos.rte.shell 7.2.4.0 7.2.4.3 key_w_fs
bos.rte.shell 7.2.5.0 7.2.5.2 key_w_fs
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.shell
REMEDIATION:
A. APARS
IBM has assigned the following APARs to this problem:
AIX Level APAR Availability SP KEY
-----------------------------------------------------
7.1.5 IJ31606 ** SP09 key_w_apar
7.2.3 IJ32285 ** N/A key_w_apar
7.2.4 IJ31614 ** SP05 key_w_apar
7.2.5 IJ31545 ** SP03 key_w_apar
VIOS Level APAR Availability SP KEY
----------------------------------------------------
3.1.0 IJ32285 ** N/A key_w_apar
3.1.1 IJ31614 ** 3.1.1.50 key_w_apar
3.1.2 IJ30557 ** 3.1.2.30 key_w_apar
Subscribe to the APARs here:
http://www.ibm.com/support/pages/apar/IJ30557
http://www.ibm.com/support/pages/apar/IJ31545
http://www.ibm.com/support/pages/apar/IJ31606
http://www.ibm.com/support/pages/apar/IJ31614
http://www.ibm.com/support/pages/apar/IJ32285
https://www.ibm.com/support/pages/apar/IJ30557
https://www.ibm.com/support/pages/apar/IJ31545
https://www.ibm.com/support/pages/apar/IJ31606
https://www.ibm.com/support/pages/apar/IJ31614
https://www.ibm.com/support/pages/apar/IJ32285
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:
ftp://aix.software.ibm.com/aix/efixes/security/ksh_fix.tar
http://aix.software.ibm.com/aix/efixes/security/ksh_fix.tar
https://aix.software.ibm.com/aix/efixes/security/ksh_fix.tar
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 (*.Z) KEY
----------------------------------------------
7.1.5.6 IJ31606s6a.210628.epkg.Z key_w_fix
7.1.5.7 IJ31606s7a.210628.epkg.Z key_w_fix
7.1.5.8 IJ31606s7a.210628.epkg.Z key_w_fix
7.2.3.5 IJ32285s4a.210628.epkg.Z key_w_fix
7.2.3.6 IJ32285s4a.210628.epkg.Z key_w_fix
7.2.3.7 IJ32285s4a.210628.epkg.Z key_w_fix
7.2.4.2 IJ31614s1a.210427.epkg.Z key_w_fix
7.2.4.3 IJ31614s1a.210427.epkg.Z key_w_fix
7.2.4.4 IJ31614s1a.210427.epkg.Z key_w_fix
7.2.5.0 IJ30557s2a.210427.epkg.Z key_w_fix
7.2.5.1 IJ30557s2a.210427.epkg.Z key_w_fix
7.2.5.2 IJ30557s2a.210427.epkg.Z key_w_fix
Please note that the above table refers to AIX TL/SP level as
opposed to fileset level, i.e., 7.2.3.5 is AIX 7200-03-05.
Please reference the Affected Products and Version section above
for help with checking installed fileset levels.
VIOS Level Interim Fix (*.Z) KEY
-----------------------------------------------
3.1.0.40 IJ32285s4a.210628.epkg.Z key_w_fix
3.1.0.50 IJ32285s4a.210628.epkg.Z key_w_fix
3.1.0.60 IJ32285s4a.210628.epkg.Z key_w_fix
3.1.1.20 IJ31614s1a.210427.epkg.Z key_w_fix
3.1.1.21 IJ31614s1a.210427.epkg.Z key_w_fix
3.1.1.25 IJ31614s1a.210427.epkg.Z key_w_fix
3.1.1.30 IJ31614s1a.210427.epkg.Z key_w_fix
3.1.1.40 IJ31614s1a.210427.epkg.Z key_w_fix
3.1.2.0 IJ30557s2a.210427.epkg.Z key_w_fix
3.1.2.10 IJ30557s2a.210427.epkg.Z key_w_fix
3.1.2.20 IJ30557s2a.210427.epkg.Z key_w_fix
3.1.2.21 IJ30557s2a.210427.epkg.Z key_w_fix
To extract the fixes from the tar file:
tar xvf ksh_fix.tar
cd ksh_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 KEY
-----------------------------------------------------------------------------------------------------
937c07cf9e42f7d0a5f2c4d3deee84da46bef49c174ffeb8d01f010d5aacd11e IJ30557s2a.210427.epkg.Z key_w_csum
764dfe4293c05298cc7325d57106850382a341127bbd9a0fefb469ff42706aa8 IJ31606s6a.210628.epkg.Z key_w_csum
de26cdab804af608be1392c53346037d7cd2de91cf67acab5d0e9d3ca988763a IJ31606s7a.210628.epkg.Z key_w_csum
2e9acbabe8632065096fe4e1ea6387af23cb495bff8e744c91205ba280bfa855 IJ31614s1a.210427.epkg.Z key_w_csum
6e7efc563989dc3a504ae9626b36053d2d58a6f3242660830c5019d67953dfa7 IJ32285s4a.210628.epkg.Z key_w_csum
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:
http://aix.software.ibm.com/aix/efixes/security/ksh_advisory.asc.sig
https://aix.software.ibm.com/aix/efixes/security/ksh_advisory.asc.sig
ftp://aix.software.ibm.com/aix/efixes/security/ksh_advisory.asc.sig
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:
http://www14.software.ibm.com/webapp/set2/sas/f/aix.efixmgmt/home.html
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.
===============================================================================
CONTACT US:
Note: Keywords labeled as KEY in this document are used for parsing
purposes.
If you would like to receive AIX Security Advisories via email,
please visit "My Notifications":
http://www.ibm.com/support/mynotifications
To view previously issued advisories, please visit:
http://www14.software.ibm.com/webapp/set2/subscriptions/onvdq
Contact IBM Support for questions related to this announcement:
http://ibm.com/support/
https://ibm.com/support/
To obtain the OpenSSL public key that can be used to verify the
signed advisories and ifixes:
Download the key from our web page:
ftp://ftp.software.ibm.com/systems/power/AIX/systems_p_os_aix_security_pubkey.txt
Please contact your local IBM AIX support center for any
assistance.
REFERENCES:
Complete CVSS v3 Guide: http://www.first.org/cvss/user-guide
On-line Calculator v3:
http://www.first.org/cvss/calculator/3.0
RELATED INFORMATION:
IBM Secure Engineering Web Portal
http://www.ibm.com/security/secure-engineering/bulletins.html
IBM Product Security Incident Response Blog
https://www.ibm.com/blogs/psirt/
Security Bulletin: Vulnerability in ksh affects AIX (CVE-2021-29741)
https://www.ibm.com/support/pages/node/6477018
ACKNOWLEDGEMENTS:
None.
CHANGE HISTORY:
First Issued: Fri Jul 30 14:43:36 CDT 2021
| Updated: Wed Aug 11 14:52:54 CDT 2021
| Update: Corrected the AIX 7.1 TL5 affected fileset levels.
===============================================================================
*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.
Related
7.2 High
CVSS2
Attack Vector
LOCAL
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
COMPLETE
Integrity Impact
COMPLETE
Availability Impact
COMPLETE
AV:L/AC:L/Au:N/C:C/I:C/A:C
7.8 High
CVSS3
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
0.0004 Low
EPSS
Percentile
5.1%