There are vulnerabilities in NTPv4 that affect AIX.

IBM SECURITY ADVISORY

First Issued: Mon Oct 26 15:14:11 CDT 2020

The most recent version of this document is available here:
http://aix.software.ibm.com/aix/efixes/security/ntp_advisory13.asc
https://aix.software.ibm.com/aix/efixes/security/ntp_advisory13.asc
ftp://aix.software.ibm.com/aix/efixes/security/ntp_advisory13.asc

Security Bulletin: Vulnerabilities in NTPv4 affect AIX (CVE-2020-11868,
CVE-2020-13817, and CVE-2020-15025)

===============================================================================

SUMMARY:

There are vulnerabilities in NTPv4 that affect AIX.

===============================================================================

VULNERABILITY DETAILS:

CVEID: CVE-2020-11868
    https://vulners.com/cve/CVE-2020-11868
    https://vulners.com/cve/CVE-2020-11868
DESCRIPTION: ntpd in ntp before 4.2.8p14 and 4.3.x before 4.3.100 allows
    an off-path attacker to block unauthenticated synchronization via a
    server mode packet with a spoofed source IP address, because
    transmissions are rescheduled even when a packet lacks a valid origin
    timestamp.
CVSS Base Score: 5.9
CVSS Temporal Score: See
    https://exchange.xforce.ibmcloud.com/vulnerabilities/180011
    for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H)

CVEID: CVE-2020-13817
    https://vulners.com/cve/CVE-2020-13817
    https://vulners.com/cve/CVE-2020-13817
DESCRIPTION: NTP is vulnerable to a denial of service, caused by an
    issue when relying on unauthenticated IPv4 time sources in ntpd.
    By predicting transmit timestamps for use in spoofed packets, a
    remote attacker could exploit this vulnerability to cause the daemon
    to crash or system time change.
CVSS Base Score: 7.4
CVSS Temporal Score: See
    https://exchange.xforce.ibmcloud.com/vulnerabilities/183494
    for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H)

CVEID: CVE-2020-15025
    https://vulners.com/cve/CVE-2020-15025
    https://vulners.com/cve/CVE-2020-15025
DESCRIPTION: ntpd in ntp 4.2.8 before 4.2.8p15 and 4.3.x before
    4.3.101 allows remote attackers to cause a denial of service
    (memory consumption) by sending packets, because memory is not freed
    in situations where a CMAC key is used and associated with a CMAC
    algorithm in the ntp.keys file.
CVSS Base Score: 4.4
CVSS Temporal Score: See
    https://exchange.xforce.ibmcloud.com/vulnerabilities/184004
    for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/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       PRODUCT(S)
    ---------------------------------------------------------------------
    ntp.rte                 7.4.2.8100   7.4.2.8130  key_w_fs  NTPv4 


    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.net.tcp.client


REMEDIATION:

    A. APARS
        
        IBM has assigned the following APARs to this problem:

        AIX Level APAR     Availability  SP   KEY         PRODUCT(S)
        ------------------------------------------------------------
        7.1.5     IJ26684  **            N/A  key_w_apar  NTPv4
        7.2.2     IJ26684  **            N/A  key_w_apar  NTPv4
        7.2.3     IJ26684  **            N/A  key_w_apar  NTPv4
        7.2.4     IJ26684  **            N/A  key_w_apar  NTPv4

        VIOS Level APAR    Availability  SP       KEY         PRODUCT(S)
        ----------------------------------------------------------------
        2.2.6      IJ26684 **            N/A      key_w_apar  NTPv4
        3.1.0      IJ26684 **            N/A      key_w_apar  NTPv4
        3.1.1      IJ26684 **            N/A      key_w_apar  NTPv4

        Subscribe to the APARs here:

        https://www.ibm.com/support/pages/apar/IJ26684

        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/VIOS fixes can be downloaded via ftp or http from:

        ftp://aix.software.ibm.com/aix/efixes/security/ntp_fix13.tar
        http://aix.software.ibm.com/aix/efixes/security/ntp_fix13.tar
        https://aix.software.ibm.com/aix/efixes/security/ntp_fix13.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        PRODUCT(S)
        ----------------------------------------------------------
        7.1.x      IJ26684s9a.200806.epkg.Z  key_w_fix  NTPv4
        7.2.x      IJ26684s9a.200806.epkg.Z  key_w_fix  NTPv4

        VIOS Level  Interim Fix (*.Z)         KEY        PRODUCT(S)
        -----------------------------------------------------------
        3.1.x       IJ26684s9a.200806.epkg.Z  key_w_fix  NTPv4

        To extract the fixes from the tar file:

        tar xvf ntp_fix13.tar 
        cd ntp_fix13

        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
        -----------------------------------------------------------------------------------------------------
        4a7e37946fae27da239e575b2a917ca5a82bbc9d31be1610b27b394d26ce9523  IJ26684s9a.200806.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 -sha1 -verify [pubkey_file] -signature [advisory_file].sig [advisory_file]

        openssl dgst -sha1 -verify [pubkey_file] -signature [ifix_file].sig [ifix_file]

        Published advisory OpenSSL signature file location:

        http://aix.software.ibm.com/aix/efixes/security/ntp_advisory13.asc.sig
        https://aix.software.ibm.com/aix/efixes/security/ntp_advisory13.asc.sig
        ftp://aix.software.ibm.com/aix/efixes/security/ntp_advisory13.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.

        The fix will not take affect until any running xntpd servers
        have been stopped and restarted with the  following commands:

            stopsrc -s xntpd
            startsrc -s xntpd

        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.

        After installation the ntp daemon must be restarted:

            stopsrc -s xntpd
            startsrc -s xntpd

        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.

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    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: Vulnerabilities in NTPv4 affect AIX (CVE-2020-11868,
    CVE-2020-13817, and CVE-2020-15025):
    https://www.ibm.com/support/pages/node/6353453

ACKNOWLEDGEMENTS:

None.

CHANGE HISTORY:

First Issued: Mon Oct 26 15:14:11 CDT 2020

===============================================================================

*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.