Security Bulletin: Multiple vulnerabilities in OpenSSL affect AIX

Summary

There are multiple vulnerabilities in OpenSSL as used by AIX. OpenSSL is used by AIX as part of AIX’s secure network communications.

Vulnerability Details

CVEID:CVE-2023-0464
**DESCRIPTION:**OpenSSL is vulnerable to a denial of service, caused by an error related to the verification of X.509 certificate chains that include policy constraints. By creating a specially crafted certificate chain that triggers exponential use of computational resources, 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/250736 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-2023-2650
**DESCRIPTION:**OpenSSL is vulnerable to a denial of service, caused by a flaw when using OBJ_obj2txt() directly, or use any of the OpenSSL subsystems OCSP, PKCS7/SMIME, CMS, CMP/CRMF or TS with no message size limit. By sending a specially crafted request, a remote attacker could exploit this vulnerability to cause a denial of service.
CVSS Base score: 7.5
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/256611 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-2023-0465
**DESCRIPTION:**OpenSSL could allow a remote attacker to bypass security restrictions, caused by a flaw when using a non-default option to verify certificates. By using invalid certificate policies in leaf certificates, an attacker could exploit this vulnerability to bypass policy checking.
CVSS Base score: 3.7
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/251293 for the current score.
CVSS Vector: (CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N)

CVEID:CVE-2023-0466
**DESCRIPTION:**OpenSSL could allow a remote attacker to bypass security restrictions, caused by a flaw in the X509_VERIFY_PARAM_add0_policy function. By using invalid certificate policies, an attacker could exploit this vulnerability to bypass certificate verification.
CVSS Base score: 3.7
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/251307 for the current score.
CVSS Vector: (CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N)

CVEID:CVE-2023-2975
**DESCRIPTION:**OpenSSL could allow a remote attacker to bypass security restrictions, caused by AES-SIV cipher implementation. By sending a specially-crafted request using empty data entries as associated data, an attacker could exploit this vulnerability to bypass authentication validation.
CVSS Base score: 5.3
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/260817 for the current score.
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N)

CVEID:CVE-2023-3446
**DESCRIPTION:**OpenSSL is vulnerable to a denial of service, caused by a flaw when using the DH_check(), DH_check_ex() or EVP_PKEY_param_check() functions to check a DH key or DH parameters. By sending a specially crafted request using long DH keys or parameters, a remote attacker could exploit this vulnerability to cause long delays, and results in a denial of service condition.
CVSS Base score: 3.7
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/261026 for the current score.
CVSS Vector: (CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L)

CVEID:CVE-2023-3817
**DESCRIPTION:**OpenSSL is vulnerable to a denial of service, caused by a flaw when using the DH_check(), DH_check_ex() or EVP_PKEY_param_check() functions to check a DH key or DH parameters. By sending a specially crafted request, a remote attacker could exploit this vulnerability to cause long delays, and results in a denial of service condition.
CVSS Base score: 3.7
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/262046 for the current score.
CVSS Vector: (CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L)

Affected Products and Versions

The following fileset levels are vulnerable:

Note:

A. 0.9.8, 1.0.1 OpenSSL versions are out-of-support. Support for OpenSSL 1.0.2 version ends by December 2023. Customers are advised to upgrade to OpenSSL 1.1.1 or 3.0 version.

B. Latest level of OpenSSL fileset is available from the web download site:

https://www.ibm.com/resources/mrs/assets?source=aixbp&S_PKG=openssl

To find out whether the affected filesets are installed on your systems, refer to the lslpp command found in the AIX user’s guide.

Example: lslpp -L | grep -i openssl.base

Remediation/Fixes

FIXES

IBM strongly recommends addressing the vulnerability now.

A fix is available, and it can be downloaded from:

https://www.ibm.com/resources/mrs/assets?source=aixbp&S_PKG=openssl

To extract the fixes from the tar file:

For OpenSSL 3.0:

zcat openssl-3.0.10.1000.tar.Z | tar xvf -

For OpenSSL 1.1.1 with no weak ciphers support:

zcat openssl-1.1.2.2200.tar.Z | tar xvf -

For OpenSSL 1.1.1 with all ciphers support:

zcat openssl-1.1.1.2200.tar.Z | tar xvf -

For OpenSSL 1.0.2:

zcat openssl-1.0.2.2107.tar.Z | tar xvf -

For OpenSSL 1.0.2 with FIPS:

zcat openssl-fips-20.16.102.2108.tar.Z | tar xvf -

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 . openssl

To install the fix package:

installp -aXYd . openssl

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/openssl_advisory39.asc.sig&gt;

Workarounds and Mitigations

None