Security Bulletin: AIX is vulnerable to denial of service due to ISC BIND (CVE-2023-2828)

Summary

A vulnerability in ISC BIND could allow a remote attacker to cause a denial of service (CVE-2023-2828). AIX uses ISC BIND as part of its DNS functions.

Vulnerability Details

CVEID:CVE-2023-2828
**DESCRIPTION:**ISC BIND is vulnerable to a denial of service, caused by a flaw that allows the named’s configured cache size limit to be significantly exceeded. By querying the resolver for specific RRsets in a certain order, a remote attacker could exploit this vulnerability to exhaust all memory on the host.
CVSS Base score: 7.5
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/258607 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

The following fileset levels are vulnerable:

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 bind.rte

Remediation/Fixes

FIXES

IBM strongly recommends addressing the vulnerability now.

AIX and VIOS fixes are available. The fixes are cumulative and address previously issued AIX/VIOS BIND security bulletins with respect to SP and TL.

The AIX and VIOS fixes can be downloaded via https from:

<https://www.ibm.com/resources/mrs/assets?source=aixbp&gt;

IMPORTANT: If possible, it is recommended that a mksysb backup of the system be created. Verify it is both bootable and readable before proceeding.

Note that all the previously reported security vulnerability fixes are also included in above mentioned fileset level. Please refer to the readme file (provided along with the fileset) for the complete list of vulnerabilities fixed.

To preview the fix installation:

installp -apYd . bind.rte

To install the fix package:

installp -aXYd . bind.rte

To verify the advisory:

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/bind_advisory24.asc.sig&gt;

Workarounds and Mitigations

None