7 High
CVSS3
Attack Vector
LOCAL
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
4.4 Medium
CVSS2
Access Vector
LOCAL
Access Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:L/AC:M/Au:N/C:P/I:P/A:P
0.001 Low
EPSS
Percentile
22.0%
IBM SECURITY ADVISORY
First Issued: Thu Jan 6 09:17:41 CST 2022
The most recent version of this document is available here:
http://aix.software.ibm.com/aix/efixes/security/openssh_advisory14.asc
https://aix.software.ibm.com/aix/efixes/security/openssh_advisory14.asc
ftp://aix.software.ibm.com/aix/efixes/security/openssh_advisory14.asc
Security Bulletin: Vulnerability in OpenSSH affects AIX (CVE-2021-41617)
===============================================================================
SUMMARY:
There is a vulnerability in OpenSSH used by AIX.
===============================================================================
VULNERABILITY DETAILS:
CVEID: CVE-2021-41617
https://vulners.com/cve/CVE-2021-41617
https://vulners.com/cve/CVE-2021-41617
DESCRIPTION: OpenSSH could allow a local attacker to gain elevated
privileges on the system, caused by an error in sshd when certain
non-default configurations are used. By executing an
AuthorizedKeysCommand or AuthorizedPrincipalsCommand, where a
AuthorizedKeysCommandUser or AuthorizedPrincipalsCommandUser
directive has been set to run the command as a non-root user, an
attacker could exploit this vulnerability to gain privileges
associated with group memberships of the sshd process.
CVSS Base Score: 7.4
CVSS Temporal Score: See
https://exchange.xforce.ibmcloud.com/vulnerabilities/210062
for the current score
CVSS Environmental Score*: Undefined
CVSS Vector:(CVSS:3.0/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H)
AFFECTED PRODUCTS AND VERSIONS:
AIX 7.1, 7.2, 7.3
VIOS 3.1
The following fileset levels are vulnerable:
key_fileset = osrcaix
Fileset Lower Level Upper Level KEY
-------------------------------------------------------------
openssh.base.client 8.1.102.2000 8.1.102.2104 key_w_fs
openssh.base.server 8.1.102.2000 8.1.102.2104 key_w_fs
Note:
A. 6.0, 7.1, 7.5 OpenSSH versions are out-of-support. Refer to AIX
release notes for supported OpenSSH versions. Customers are
advised to upgrade to currently supported OpenSSH 8.1 version.
B. Latest level of OpenSSH fileset is available from the web
download site:
https://www.ibm.com/resources/mrs/assets?source=aixbp&S_PKG=openssh
To determine if your system is vulnerable, execute the
following commands:
lslpp -L | grep -i openssh.base.client
lslpp -L | grep -i openssh.base.server
REMEDIATION:
A. FIXES
The fixes can be downloaded via ftp or http from:
ftp://aix.software.ibm.com/aix/efixes/security/openssh_fix14.tar
http://aix.software.ibm.com/aix/efixes/security/openssh_fix14.tar
https://aix.software.ibm.com/aix/efixes/security/openssh_fix14.tar
The links above are 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.
Note that the tar file contains Interim fixes that are based on
OpenSSL version, and AIX OpenSSL fixes are cumulative.
You must be on the 'prereq for installation' level before
applying the interim fix. This may require installing a new
level(prereq version) first.
AIX Level Interim Fix (*.Z) Fileset Name(prereq for installation) KEY
---------------------------------------------------------------------------------------
7.1, 7.2 41617s9a.211029.epkg.Z openssh.base(8.1.102.2103) key_w_fix
VIOS Level Interim Fix (*.Z) Fileset Name(prereq for installation) KEY
--------------------------------------------------------------------------------------------
3.1.x 41617s9a.211029.epkg.Z openssh.base(8.1.102.2103) key_w_fix
To extract the fixes from the tar file:
tar xvf openssh_fix14.tar
cd openssh_fix14
Verify you have retrieved the fixes intact:
The checksums below were generated using the
"openssl dgst -sha256 [file]" command as the following:
openssl dgst -sha256 filename KEY
-----------------------------------------------------------------------------------------------------
1d134a4f95413d2e79ac5e9d577692602295cf524e9611916987b478a5b0d547 41617s9a.211029.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 AIX Support at
https://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/openssh_advisory14.asc.sig
https://aix.software.ibm.com/aix/efixes/security/openssh_advisory14.asc.sig
ftp://aix.software.ibm.com/aix/efixes/security/openssh_advisory14.asc.sig
B. FIX AND INTERIM FIX INSTALLATION
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
https://www.ibm.com/support/mynotifications
To view previously issued advisories, please visit:
http://www14.software.ibm.com/webapp/set2/subscriptions/onvdq
https://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
https://www.first.org/cvss/user-guide
On-line Calculator v3:
http://www.first.org/cvss/calculator/3.0
https://www.first.org/cvss/calculator/3.0
RELATED INFORMATION:
Security Bulletin: Vulnerability in OpenSSH affects AIX (CVE-2021-41617)
https://www.ibm.com/support/pages/node/6538690
ACKNOWLEDGEMENTS:
None.
CHANGE HISTORY:
First Issued: Thu Jan 6 09:17:41 CST 2022
===============================================================================
*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.
7 High
CVSS3
Attack Vector
LOCAL
Attack Complexity
HIGH
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
4.4 Medium
CVSS2
Access Vector
LOCAL
Access Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:L/AC:M/Au:N/C:P/I:P/A:P
0.001 Low
EPSS
Percentile
22.0%