Lucene search

K
ibmIBMC29B594A3B1447B1A45250C0EB10212AE463A1A60DC4473788F098AE8EE201B4
HistoryOct 11, 2023 - 7:02 p.m.

Security Bulletin: AIX is vulnerable to a denial of service due to libxml2 (CVE-2023-29469 and CVE-2023-28484)

2023-10-1119:02:33
www.ibm.com
86
vulnerability
aix
libxml2

CVSS3

6.5

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

REQUIRED

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

EPSS

0.001

Percentile

46.5%

Summary

Vulnerabilities in libxml2 could allow a remote attacker to cause a denial of service (CVE-2023-29469 and CVE-2023-28484). AIX uses libxml2 as part of its XML parsing functions.

Vulnerability Details

CVEID:CVE-2023-29469
**DESCRIPTION:**GNOME libxml2 is vulnerable to a denial of service, caused by a double free flaw in the xmlDictComputeFastKey function due to hashing empty strings are not null-terminated. By persuading a victim to open a specially crafted XML content, a remote attacker could exploit this vulnerability to cause a denial of service condition.
CVSS Base score: 5.5
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/253143 for the current score.
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H)

CVEID:CVE-2023-28484
**DESCRIPTION:**GNOME libxml2 is vulnerable to a denial of service, caused by a NULL pointer dereference flaw in the xmlSchemaFixupComplexType function. By persuading a victim to open a specially crafted XML content, a remote attacker could exploit this vulnerability to cause a denial of service condition.
CVSS Base score: 5.5
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/253138 for the current score.
CVSS Vector: (CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H)

Affected Products and Versions

Affected Product(s) Version(s)
AIX 7.2
AIX 7.3
VIOS 3.1

The following fileset levels are vulnerable:

Fileset Lower Level Upper Level
bos.rte.control 7.2.5.0 7.2.5.6
bos.rte.control 7.2.5.100 7.2.5.103
bos.rte.control 7.2.5.200 7.2.5.201
bos.rte.control 7.3.0.0 7.3.0.3
bos.rte.control 7.3.1.0 7.3.1.1

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 bos.rte.control

Remediation/Fixes

A. APARS

IBM has assigned the following APARs to this problem:

AIX Level APAR SP
7.2.5 IJ47597 SP07
7.3.0 IJ47629 N/A
7.3.1 IJ47630 SP03
VIOS Level APAR SP
3.1.2 IJ47631 N/A
3.1.3 IJ47632 3.1.3.50
3.1.4 IJ47597 3.1.4.30

Subscribe to the APARs here:

<https://www.ibm.com/support/pages/apar/IJ47597&gt;

<https://www.ibm.com/support/pages/apar/IJ47629&gt;

<https://www.ibm.com/support/pages/apar/IJ47630&gt;

<https://www.ibm.com/support/pages/apar/IJ47631&gt;

<https://www.ibm.com/support/pages/apar/IJ47632&gt;

By subscribing, you will receive periodic email alerting you to the status of the APAR, and a link to download the fix once it becomes available.

B. FIXES

IBM strongly recommends addressing the vulnerability now.

AIX and VIOS fixes are available. The fixes are cumulative and address previously issued AIX/VIOS libxml2 security bulletins with respect to SP and TL:

<https://aix.software.ibm.com/aix/efixes/security/libxml2_advisory4.asc&gt;

<https://www.ibm.com/support/pages/node/6953825&gt;

<https://aix.software.ibm.com/aix/efixes/security/libxml2_advisory3.asc&gt;

<https://www.ibm.com/support/pages/node/6619729&gt;

The AIX and VIOS fixes can be downloaded via ftp or http from:

<https://aix.software.ibm.com/aix/efixes/security/libxml2_fix5.tar&gt;

The link above is to a tar file containing this signed advisory, fix packages, and OpenSSL signatures for each package. The fixes below include prerequisite checking. This will enforce the correct mapping between the fixes and AIX Technology Levels.

AIX Level Interim Fix
7.2.5.4 IJ47597m4a.230718.epkg.Z
7.2.5.5 IJ47597m6a.230717.epkg.Z
7.2.5.6 IJ47597m6a.230717.epkg.Z
7.3.0.2 IJ47629m4a.230718.epkg.Z
7.3.0.3 IJ47629m4a.230718.epkg.Z
7.3.0.4 IJ47629m4a.230718.epkg.Z
7.3.1.1 IJ47630m2a.230718.epkg.Z
7.3.1.2 IJ47630m2a.230718.epkg.Z

Please note that the above table refers to AIX TL/SP level as opposed to fileset level, i.e., 7.3.0.3 is AIX 7300-00-03.

Please reference the Affected Products and Version section above for help with checking installed fileset levels.

VIOS Level Interim Fix
3.1.2.40 IJ47631m6a.230718.epkg.Z
3.1.2.50 IJ47631m6a.230718.epkg.Z
3.1.2.60 IJ47631m6a.230718.epkg.Z
3.1.3.21 IJ47632m4a.230718.epkg.Z
3.1.3.30 IJ47632m4a.230718.epkg.Z
3.1.3.40 IJ47632m4a.230718.epkg.Z
3.1.4.10 IJ47597m6a.230717.epkg.Z
3.1.4.21 IJ47597m6a.230717.epkg.Z

To extract the fixes from the tar file:

tar xvf libxml2_fix5.tar

cd libxml2_fix5

Verify you have retrieved the fixes intact:

The checksums below were generated using the β€œopenssl dgst -sha256 [filename]” command as the following:

openssl dgst -sha256 filename
3d2d1242eb42fadb11d1c3e9625a81bdf3f605a465039b7592d46ab401e68af7 IJ47597m4a.230718.epkg.Z
c06c96eeae459c2533b0d2df958f31aafbcc6c274a732324039328ee7a272f97 IJ47597m6a.230717.epkg.Z
b80ac199295a15227b8e946ff5db42324e62e40bbfbb59d81f5b2627286e505b IJ47629m4a.230718.epkg.Z
85b4de5a3bd7098cb808f48a9ceb40f3aefddae418e902f42691f68882d850c8 IJ47630m2a.230718.epkg.Z
a72eb5c8c9012a0a3d9b4789b257e29740720f4a1948c2971d6dafd77ecccadc IJ47631m6a.230718.epkg.Z
38539a5de0ac8961a32bb5e872a79d4bee66b5de6735c9f049f2decc6dac581c IJ47632m4a.230718.epkg.Z

These sums should match exactly. The OpenSSL signatures in the tar file and on this advisory can also be used to verify the integrity of the fixes. If the sums or signatures cannot be confirmed, contact IBM Support at <http://ibm.com/support/&gt; and describe the discrepancy.

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/libxml2_advisory5.asc.sig&gt;

C. FIX AND INTERIM FIX INSTALLATION

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

To preview a fix installation:

installp -a -d fix_name -p all # where fix_name is the name of the

fix package being previewed.

To install a fix package:

installp -a -d fix_name -X all # where fix_name is the name of the

fix package being installed.

Interim fixes have had limited functional and regression testing but not the full regression testing that takes place for Service Packs; however, IBM does fully support them.

Interim fix management documentation can be found at:

<http://www14.software.ibm.com/webapp/set2/sas/f/aix.efixmgmt/home.html&gt;

To preview an interim fix installation:

emgr -e ipkg_name -p # where ipkg_name is the name of the

interim fix package being previewed.

To install an interim fix package:

emgr -e ipkg_name -X # where ipkg_name is the name of the

interim fix package being installed.

Workarounds and Mitigations

None

Affected configurations

Vulners
Node
ibmaixMatch7.2
OR
ibmaixMatch7.3
OR
ibmpowervm_virtual_i\/o_serverMatch3.1

CVSS3

6.5

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

NONE

User Interaction

REQUIRED

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

EPSS

0.001

Percentile

46.5%