Security Bulletin: ISC BIND on IBM i is vulnerable to denial of service due to memory leaks and a flaw in resolver code (CVE-2022-2795, CVE-2022-38177, CVE-2022-38178)

Summary

ISC BIND on IBM i is vulnerable to a denial of service attack due to memory leaks in the DNSSEC verification code and a flaw in resolver code to degrade performance as described in the vulnerability details section. IBM i has addressed the vulnerabilities in ISC BIND with a fix as described in the remediation/fixes section.

Vulnerability Details

CVEID:   CVE-2022-2795
DESCRIPTION:   ISC BIND is vulnerable to a denial of service, caused by a flaw in resolver code. By flooding the target resolver with queries, a remote attacker could exploit this vulnerability to severely degrade the resolver’s performance, effectively denying legitimate clients access to the DNS resolution service.
CVSS Base score: 5.3
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/236701 for the current score.
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L)

CVEID:   CVE-2022-38177
DESCRIPTION:   ISC BIND is vulnerable to a denial of service, caused by a small memory leak in the DNSSEC verification code for the ECDSA algorithm. By spoofing the target resolver with responses that have a malformed ECDSA signature, a remote attacker could exploit this vulnerability to cause named to crash.
CVSS Base score: 7.5
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/236705 for the current score.
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H)

CVEID:   CVE-2022-38178
DESCRIPTION:   ISC BIND is vulnerable to a denial of service, caused by a memory leak in the DNSSEC verification code for the EdDSA algorithm. By spoofing the target resolver with responses that have a malformed EdDSA signature, a remote attacker could exploit this vulnerability to cause named to crash.
CVSS Base score: 7.5
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/236706 for the current score.
CVSS Vector: (CVSS:3.0/AV:N/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 PTFs to IBM i.  IBM i releases 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

28 Nov 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.