CVSS3
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
LOW
Integrity Impact
LOW
Availability Impact
LOW
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:L
EPSS
Percentile
37.9%
IBM SECURITY ADVISORY
First Issued: Thu Oct 5 10:43:28 CDT 2023
The most recent version of this document is available here:
https://aix.software.ibm.com/aix/efixes/security/ntp_advisory14.asc
Security Bulletin: AIX is vulnerable to a denial of service due to NTP
(CVE-2023-26551, CVE-2023-26552, CVE-2023-26553, CVE-2023-26554)
===============================================================================
SUMMARY:
Multiple vulnerabilities in NTP could allow a remote attacker to cause a
denial of service (CVE-2023-26551, CVE-2023-26552, CVE-2023-26553,
CVE-2023-26554).
===============================================================================
VULNERABILITY DETAILS:
CVEID: CVE-2023-26551
https://vulners.com/cve/CVE-2023-26551
DESCRIPTION: NTP is vulnerable to a denial of service, caused by an
out-of-bounds write in mstolfp in libntp/mstolfp.c. By sending a
specially-crafted request, a remote attacker could exploit this
vulnerability to cause a denial of service.
CVSS Base Score: 5.3
CVSS Temporal Score: See
https://exchange.xforce.ibmcloud.com/vulnerabilities/252595
for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L)
CVEID: CVE-2023-26552
https://vulners.com/cve/CVE-2023-26552
DESCRIPTION: NTP is vulnerable to a denial of service, caused by an
out-of-bounds write in mstolfp in libntp/mstolfp.c. By sending a
specially-crafted request, a remote attacker could exploit this
vulnerability to cause a denial of service.
CVSS Base Score: 5.3
CVSS Temporal Score: See
https://exchange.xforce.ibmcloud.com/vulnerabilities/252594
for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L)
CVEID: CVE-2023-26553
https://vulners.com/cve/CVE-2023-26553
DESCRIPTION: NTP is vulnerable to a denial of service, caused by an
out-of-bounds write in mstolfp in libntp/mstolfp.c. By sending a
specially-crafted request, a remote attacker could exploit this
vulnerability to cause a denial of service.
CVSS Base Score: 5.3
CVSS Temporal Score: See
https://exchange.xforce.ibmcloud.com/vulnerabilities/252593
for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L)
CVEID: CVE-2023-26554
https://vulners.com/cve/CVE-2023-26554
DESCRIPTION: NTP is vulnerable to a denial of service, caused by an
out-of-bounds write in mstolfp in libntp/mstolfp.c. By sending a
specially-crafted request, a remote attacker could exploit this
vulnerability to cause a denial of service.
CVSS Base Score: 5.3
CVSS Temporal Score: See
https://exchange.xforce.ibmcloud.com/vulnerabilities/252592
for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L)
AFFECTED PRODUCTS AND VERSIONS:
AIX 7.2, 7.3
VIOS 3.1
The vulnerabilities in the following filesets are being addressed:
key_fileset = aix
Fileset Lower Level Upper Level KEY
---------------------------------------------------------
ntp.rte 7.4.2.8100 7.4.2.8153 key_w_fs
ntp.rte 73.4.2.8151 73.4.2.8154 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 ntp.rte
REMEDIATION:
A. APARS
IBM has assigned the following APARs to this problem:
AIX Level APAR Availability SP KEY
-----------------------------------------------------
7.2 IJ47973 ** N/A key_w_apar
7.3 IJ47974 ** N/A key_w_apar
VIOS Level APAR Availability SP KEY
-----------------------------------------------------
3.1 IJ47973 ** N/A key_w_apar
Subscribe to the APARs here:
https://www.ibm.com/support/pages/apar/[APAR Number]
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
IBM strongly recommends addressing the vulnerability now.
AIX and VIOS fixes are available. The fixes are cumulative and
address previously issued AIX/VIOS NTP security bulletins with
respect to fileset level.
The AIX and VIOS fixes can be downloaded via https from:
https://aix.software.ibm.com/aix/efixes/security/ntp_fix14.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
----------------------------------------------
7.2 IJ47973s6a.230829.epkg.Z key_w_fix
7.3 IJ47974s4a.230829.epkg.Z key_w_fix
VIOS Level Interim Fix (*.Z) KEY
-----------------------------------------------
3.1 IJ47973s6a.230829.epkg.Z key_w_fix
To extract the fixes from the tar file:
tar xvf ntp_fix14.tar
cd ntp_fix14
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
-----------------------------------------------------------------------------------------------------
f79d53ff1de803f3ee2d30e5cd9bf6082559a26e27cc18706877e114c46bbb68 IJ47973s6a.230829.epkg.Z key_w_csum
5eba38fa620746c76c6fa6ba249d2dfced28fbabafc4042789908eda2dbe9dff IJ47974s4a.230829.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:
https://aix.software.ibm.com/aix/efixes/security/ntp_advisory14.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:
https://www.ibm.com/support/pages/managing-interim-fixes-aix
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":
https://www.ibm.com/support/mynotifications
Contact IBM Support for questions related to this announcement:
https://ibm.com/support/
For information on how to securely verify AIX security bulletins and fixes:
https://www.ibm.com/support/pages/node/6985269
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
https://aix.software.ibm.com/aix/efixes/security/systems_p_os_aix_security_pubkey.txt
To verify the AIX/VIOS security bulletin:
Published advisory OpenSSL signature file location:
https://aix.software.ibm.com/aix/efixes/security/ntp_advisory14.asc.sig
openssl dgst -sha256 -verify [pubkey_file] -signature [advisory_file].sig [advisory_file]
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: AIX is vulnerable to a denial of service due to NTP
(CVE-2023-26551, CVE-2023-26552, CVE-2023-26553, CVE-2023-26554)
https://www.ibm.com/support/pages/node/7047270
ACKNOWLEDGEMENTS:
None.
CHANGE HISTORY:
First Issued: Thu Oct 5 10:43:28 CDT 2023
===============================================================================
*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.