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Security Bulletin: IBM i is vulnerable to an out-of-bounds write in NTP services due to multiple vulnerabilities.

Security Bulletin


Summary

IBM i is vulnerable to an out-of-bounds write due to a flaw in mstolfp.c in NTP [CVE-2023-26551, CVE-2023-26552, CVE-2023-26553, and CVE-2023-26554] as described in the vulnerability details section. This bulletin identifies the steps to take to address the vulnerabilities as described in the remediation/fixes section.

Vulnerability Details

CVEID:   CVE-2023-26553
DESCRIPTION:   mstolfp in libntp/mstolfp.c in NTP 4.2.8p15 has an out-of-bounds write when copying the trailing number. An adversary may be able to attack a client ntpq process, but cannot attack ntpd.
CWE:   CWE-787: Out-of-bounds Write
CVSS Source:   IBM X-Force
CVSS Base score:   5.3
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
DESCRIPTION:   mstolfp in libntp/mstolfp.c in NTP 4.2.8p15 has an out-of-bounds write when adding a '\0' character. An adversary may be able to attack a client ntpq process, but cannot attack ntpd.
CWE:   CWE-787: Out-of-bounds Write
CVSS Source:   IBM X-Force
CVSS Base score:   5.3
CVSS Vector:   (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L)

CVEID:   CVE-2023-26551
DESCRIPTION:   mstolfp in libntp/mstolfp.c in NTP 4.2.8p15 has an out-of-bounds write in the cp
CWE:   CWE-787: Out-of-bounds Write
CVSS Source:   IBM X-Force
CVSS Base score:   5.3
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
DESCRIPTION:   mstolfp in libntp/mstolfp.c in NTP 4.2.8p15 has an out-of-bounds write when adding a decimal point. An adversary may be able to attack a client ntpq process, but cannot attack ntpd.
CWE:   CWE-787: Out-of-bounds Write
CVSS Source:   IBM X-Force
CVSS Base score:   5.3
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

Affected Product(s)Version(s)
IBM i7.5
IBM i7.4
IBM i7.3

Remediation/Fixes

The issue can be addressed by applying a PTF to IBM i that upgrades the NTP version.  The NTP version upgrade happened for the IBM i 7.5 and 7.4 releases during a scheduled 2024 currency update.  The IBM i 7.3 release NTP version is now updated in response to these vulnerabilities.
The IBM i 5770-SS1 PTF numbers contain the fix to resolve the vulnerabilities.

 

https://www.ibm.com/support/fixcentral

Important note: IBM recommends that all users running unsupported versions of affected products upgrade to supported and fixed version of affected products.

Workarounds and Mitigations

None.

Get Notified about Future Security Bulletins

References

Off

Acknowledgement

Change History

11 Apr 2025: Initial Publication

*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. In addition to other efforts to address potential vulnerabilities, IBM periodically updates the record of components contained in our product offerings. As part of that effort, if IBM identifies previously unidentified packages in a product/service inventory, we address relevant vulnerabilities regardless of CVE date. Inclusion of an older CVEID does not demonstrate that the referenced product has been used by IBM since that date, nor that IBM was aware of a vulnerability as of that date. We are making clients aware of relevant vulnerabilities as we become aware of them. "Affected Products and Versions" referenced in IBM Security Bulletins are intended to be only products and versions that are supported by IBM and have not passed their end-of-support or warranty date. Thus, failure to reference unsupported or extended-support products and versions in this Security Bulletin does not constitute a determination by IBM that they are unaffected by the vulnerability. Reference to one or more unsupported versions in this Security Bulletin shall not create an obligation for IBM to provide fixes for any unsupported or extended-support products or versions.

Document Location

Worldwide

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Document Information

Modified date:
11 April 2025

Initial Publish date:
11 April 2025

UID

ibm17230794