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aixCentOS ProjectOPENSSH_ADVISORY14.ASC
HistoryJan 06, 2022 - 9:17 a.m.

Vulnerabilities in OpenSSH affect AIX.

2022-01-0609:17:41
CentOS Project
aix.software.ibm.com
172

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%