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HistoryOct 31, 2023 - 9:28 p.m.

Security Bulletin: AIX is vulnerable to a denial of service due to libxml2 (CVE-2022-29824)

2023-10-3121:28:38
www.ibm.com
148

6.5 Medium

CVSS3

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

7.3 High

AI Score

Confidence

High

4.3 Medium

CVSS2

Access Vector

NETWORK

Access Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

PARTIAL

AV:N/AC:M/Au:N/C:N/I:N/A:P

0.002 Low

EPSS

Percentile

50.2%

Summary

UPDATED Dec 12 2022 (Added iFixes for AIX 7.2 TL5 SP5 and VIOS 3.1.4.10): A vulnerability in libxml2 could allow a remote attacker to cause a denial of service (CVE-2022-29824). AIX uses libxml2 as part of its XML parsing functions.

Vulnerability Details

CVEID:CVE-2022-29824
**DESCRIPTION:GNOME libxml2 is vulnerable to a denial of service, caused by an integer overflows in several buffer handling functions in buf.c (xmlBuf) and tree.c (xmlBuffer). By persuading a victim to open a specially-crafted XML file, 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/225645 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 7.2.4.0 7.2.4.5
bos.rte.control 7.2.5.0 7.2.5.4
bos.rte.control 7.2.5.100 7.2.5.101
bos.rte.control 7.2.5.200 7.2.5.201
bos.rte.control 7.3.0.0 7.3.0.1

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
7.2.4 IJ42381 N/A
7.2.5 IJ45056 SP07
7.3.0 IJ45059 SP04
VIOS Level APAR SP
3.1.1 IJ42381 N/A
3.1.2 IJ45057 3.1.2.60
3.1.3 IJ45058 3.1.3.40
3.1.4 IJ45056 3.1.4.30

Subscribe to the APARs here:

<https://www.ibm.com/support/pages/apar/IJ42339&gt;

<https://www.ibm.com/support/pages/apar/IJ42341&gt;

<https://www.ibm.com/support/pages/apar/IJ42378&gt;

<https://www.ibm.com/support/pages/apar/IJ42379&gt;

<https://www.ibm.com/support/pages/apar/IJ42381&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 AIX and VIOS fixes can be downloaded via ftp or http from:

ftp://aix.software.ibm.com/aix/efixes/security/libxml2_fix3.tar

<http://aix.software.ibm.com/aix/efixes/security/libxml2_fix3.tar&gt;

<https://aix.software.ibm.com/aix/efixes/security/libxml2_fix3.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
7.2.4.4 IJ42381s6a.220909.epkg.Z
7.2.4.5 IJ42381s6a.220909.epkg.Z
7.2.4.6 IJ42381s6a.220909.epkg.Z
7.2.5.2 IJ42339s2a.220909.epkg.Z
7.2.5.3 IJ42339s4a.220907.epkg.Z
7.2.5.4 IJ42339s4a.220907.epkg.Z
7.2.5.5 IJ42339s5a.221212.epkg.Z
7.3.0.1 IJ42341s2a.220907.epkg.Z
7.3.0.2 IJ42341s2a.220907.epkg.Z

Please note that the above table refers to AIX TL/SP level as opposed to fileset level, i.e., 7.2.5.2 is AIX 7200-05-02.

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

VIOS Level Interim Fix
3.1.1.40 IJ42381s6a.220909.epkg.Z
3.1.1.50 IJ42381s6a.220909.epkg.Z
3.1.1.60 IJ42381s6a.220909.epkg.Z
3.1.2.21 IJ42378s2a.220909.epkg.Z
3.1.2.30 IJ42378s2a.221010.epkg.Z
3.1.2.40 IJ42378s2a.221010.epkg.Z
3.1.3.10 IJ42379s4a.220909.epkg.Z
3.1.3.14 IJ42379s4a.220909.epkg.Z
3.1.3.21 IJ42379s4a.220909.epkg.Z
3.1.4.10 IJ42339s5a.221212.epkg.Z

To extract the fixes from the tar file:

tar xvf libxml2_fix3.tar

cd libxml2_fix3

Verify you have retrieved the fixes intact:

The checksums below were generated using the “openssl dgst -sha256 [filename]” command as the following:

openssl dgst -sha256 filename
f6d71f263ee414469dde9e6c3325fbc56031d3098ee8831f330e90c9e6b4dd9a IJ42339s2a.220909.epkg.Z
062b34620bc669451695f0de09580aef6e16f36f6430654dee5c403d23bc2fcc IJ42339s4a.220907.epkg.Z
6a76b4c66b2ff7022b6a00eb2348b4c930af7293692631367f08e4bc65a753df IJ42339s5a.221212.epkg.Z
562b5f19d4db9e4c8835fd92f2e65038c2d765f0ff5e3ef40bad2d9110403a26 IJ42341s2a.220907.epkg.Z
f5ec81e718eef7d02adfb85a70f626073f684b93d72173212ba5675fe1eff001 IJ42378s2a.220909.epkg.Z
6d32716245fee8bc45fb961754eb53aaabc8630eb1e999c1e67cee237cc058cd IJ42378s2a.221010.epkg.Z
e00696e638622f82a2264b994fff9415b55c323a271da4c4bb84626046aa031c IJ42379s4a.220909.epkg.Z
f03c422e62ea819fa2dfc56342a16da80d20df4444667c6fae97ae95c1c2f6dd IJ42381s6a.220909.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:

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

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

ftp://aix.software.ibm.com/aix/efixes/security/libxml2_advisory3.asc.sig

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

CPENameOperatorVersion
powervm virtual i/o servereq3.1

6.5 Medium

CVSS3

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

7.3 High

AI Score

Confidence

High

4.3 Medium

CVSS2

Access Vector

NETWORK

Access Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

PARTIAL

AV:N/AC:M/Au:N/C:N/I:N/A:P

0.002 Low

EPSS

Percentile

50.2%

Related for 6E896C3EA4E119BB94E79619FA7DDA4DD85C924131CFD25FA41D57AE7BF850C4