Security Bulletin: ISC DHCP server for IBM i is vulnerable to a denial of service attack due to a memory leak and refererence count overflow (CVE-2022-2928, CVE-2022-2929)

Summary

ISC DHCP server on IBM i is vulnerable to a denial of service attack due to a memory leak in the fqdn_universe_decode function and a reference count overflow in the add_option function as described in the vulnerability details section. IBM i has addressed the vulnerabilities in ISC DHCP server with a fix as described in the remediation/fixes section.

Vulnerability Details

CVEID:   CVE-2022-2929
DESCRIPTION:   ISC DHCP is vulnerable to a denial of service, caused by a memory leak in the fqdn_universe_decode() function. By sending specially crafted DHCP packets for an extended period of time, a remote attacker from within the local network could exploit this vulnerability to cause the server to run out of memory.
CVSS Base score: 6.5
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/237823 for the current score.
CVSS Vector: (CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

CVEID:   CVE-2022-2928
DESCRIPTION:   ISC DHCP is vulnerable to a denial of service, caused by an option refcount overflow in the add_option() function. A remote attacker from within the local network could exploit this vulnerability to overflow the reference counters and cause the server to abort.
CVSS Base score: 6.5
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/237822 for the current score.
CVSS Vector: (CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

Affected Products and Versions

Affected Product(s)Version(s)IBM i7.5IBM i7.4IBM i7.3IBM i7.2

Remediation/Fixes

The issue can be fixed by applying a PTF to IBM i.  IBM i 7.5, 7.4, 7.3, and 7.2 will be fixed.

The IBM i PTF numbers contain the fix for 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

Change History

02 Dec 2022: 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.