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AUSCERT External Security Bulletin Redistribution
ESB-2020.4512
Security Bulletin: Vulnerability in BIND affects AIX (CVE-2020-8622)
21 December 2020
===========================================================================
AusCERT Security Bulletin Summary
---------------------------------
Product: AIX
Publisher: IBM
Operating System: AIX
Impact/Access: Denial of Service -- Existing Account
Resolution: Patch/Upgrade
CVE Names: CVE-2020-8622
Reference: ESB-2020.4179
ESB-2020.4178
ESB-2020.3970
ESB-2020.3880
Original Bulletin:
https://www.ibm.com/support/pages/node/6388720
- --------------------------BEGIN INCLUDED TEXT--------------------
Vulnerability in BIND affects AIX (CVE-2020-8622)
Document Information
Document number : 6388720
Modified date : 18 December 2020
Product : AIX
Software version : 7.1,7.2
Operating system(s): AIX
Summary
There is a vulnerability in BIND that affects AIX.
Vulnerability Details
CVEID: CVE-2020-8622
DESCRIPTION: ISC BIND is vulnerable to a denial of service, caused by an
assertion failure when attempting to verify a truncated response to a
TSIG-signed request. By sending a specially-crafted request, a remote
authenticated attacker could exploit this vulnerability to cause the server to
exit.
CVSS Base score: 6.5
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/
187060 for the current score.
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
Affected Products and Versions
+--------------------+----------+
|Affected Product(s) |Version(s)|
+--------------------+----------+
|AIX |7.1 |
+--------------------+----------+
|AIX |7.2 |
+--------------------+----------+
|VIOS |3.1 |
+--------------------+----------+
The following fileset levels are vulnerable:
+----------------------+-----------+-----------+
|Fileset |Lower Level|Upper Level|
+----------------------+-----------+-----------+
|bos.net.tcp.client |7.1.5.0 |7.1.5.36 |
+----------------------+-----------+-----------+
|bos.net.tcp.bind_utils|7.2.3.0 |7.2.3.16 |
+----------------------+-----------+-----------+
|bos.net.tcp.bind_utils|7.2.4.0 |7.2.4.1 |
+----------------------+-----------+-----------+
|bos.net.tcp.bind_utils|7.2.5.0 |7.2.5.1 |
+----------------------+-----------+-----------+
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.net.tcp.client
Remediation/Fixes
A. APARS
IBM has assigned the following APARs to this problem:
+----------+-------+----+
|AIX Level |APAR |SP |
+----------+-------+----+
|7.1.5 |IJ29230|SP08|
+----------+-------+----+
|7.2.3 |IJ29229|SP07|
+----------+-------+----+
|7.2.4 |IJ29231|SP04|
+----------+-------+----+
|7.2.5 |IJ29232|SP02|
+----------+-------+----+
+-----------+-------+--------+
|VIOS Level |APAR |SP |
+-----------+-------+--------+
|3.1.0 |IJ29229|3.1.0.60|
+-----------+-------+--------+
|3.1.1 |IJ29231|3.1.1.40|
+-----------+-------+--------+
|3.1.2 |IJ29232|3.1.2.20|
+-----------+-------+--------+
Subscribe to the APARs here:
http://www.ibm.com/support/pages/apar/IJ29229
http://www.ibm.com/support/pages/apar/IJ29230
http://www.ibm.com/support/pages/apar/IJ29231
http://www.ibm.com/support/pages/apar/IJ29232
https://www.ibm.com/support/pages/apar/IJ29229
https://www.ibm.com/support/pages/apar/IJ29230
https://www.ibm.com/support/pages/apar/IJ29231
https://www.ibm.com/support/pages/apar/IJ29232
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
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/bind_fix18.tar
http://aix.software.ibm.com/aix/efixes/security/bind_fix18.tar
https://aix.software.ibm.com/aix/efixes/security/bind_fix18.tar
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 |
+---------+------------------------+
|7.1.5.5 |IJ29230m7a.201117.epkg.Z|
+---------+------------------------+
|7.1.5.6 |IJ29230m7a.201117.epkg.Z|
+---------+------------------------+
|7.1.5.7 |IJ29230m7a.201117.epkg.Z|
+---------+------------------------+
|7.2.3.3 |IJ29229m5a.201117.epkg.Z|
+---------+------------------------+
|7.2.3.4 |IJ29229m5a.201117.epkg.Z|
+---------+------------------------+
|7.2.3.5 |IJ29229m5a.201117.epkg.Z|
+---------+------------------------+
|7.2.4.0 |IJ29231m2a.201117.epkg.Z|
+---------+------------------------+
|7.2.4.1 |IJ29231m2a.201117.epkg.Z|
+---------+------------------------+
|7.2.4.2 |IJ29231m2a.201117.epkg.Z|
+---------+------------------------+
|7.2.5.0 |IJ29232s1a.201117.epkg.Z|
+---------+------------------------+
|7.2.5.1 |IJ29232s1a.201117.epkg.Z|
+---------+------------------------+
Please note that the above table refers to AIX TL/SP level as opposed to
fileset level, i.e., 7.2.3.5 is AIX 7200-03-05.
Please reference the Affected Products and Version section above for help with
checking installed fileset levels.
+----------+------------------------+
|VIOS Level|Interim Fix |
+----------+------------------------+
|3.1.0.20 |IJ29229m5a.201117.epkg.Z|
+----------+------------------------+
|3.1.0.21 |IJ29229m5a.201117.epkg.Z|
+----------+------------------------+
|3.1.0.30 |IJ29229m5a.201117.epkg.Z|
+----------+------------------------+
|3.1.0.40 |IJ29229m5a.201117.epkg.Z|
+----------+------------------------+
|3.1.1.0 |IJ29231m2a.201117.epkg.Z|
+----------+------------------------+
|3.1.1.10 |IJ29231m2a.201117.epkg.Z|
+----------+------------------------+
|3.1.1.20 |IJ29231m2a.201117.epkg.Z|
+----------+------------------------+
|3.1.1.21 |IJ29231m2a.201117.epkg.Z|
+----------+------------------------+
|3.1.1.22 |IJ29231m2a.201117.epkg.Z|
+----------+------------------------+
|3.1.1.25 |IJ29231m2a.201117.epkg.Z|
+----------+------------------------+
|3.1.2.0 |IJ29232s1a.201117.epkg.Z|
+----------+------------------------+
|3.1.2.10 |IJ29232s1a.201117.epkg.Z|
+----------+------------------------+
To extract the fixes from the tar file:
tar xvf bind_fix18.tar
cd bind_fix18
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 |
+----------------------------------------------------------------+------------------------+
|2277f723175f912ef8ac6d4389b1ee4ffdeafad4793df0e1c3dc018416dabc34|IJ29229m5a.201117.epkg.Z|
+----------------------------------------------------------------+------------------------+
|49b979992aecad5cbb085e3f0ea84091205a47fdbdafc076e5353f3fbab4d565|IJ29230m7a.201117.epkg.Z|
+----------------------------------------------------------------+------------------------+
|d907c4aea95f4de1378f9fcb89460dc11e6cda8224ee2f1071764ddf6c275d20|IJ29231m2a.201117.epkg.Z|
+----------------------------------------------------------------+------------------------+
|2af0db1aebde06628627b84e976fe676e8232b70b9fca7439e62060b8c18b611|IJ29232s1a.201117.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/ and describe the discrepancy.
openssl dgst -sha1 -verify [pubkey_file] -signature [advisory_file].sig
[advisory_file]
openssl dgst -sha1 -verify [pubkey_file] -signature [ifix_file].sig [ifix_file]
Published advisory OpenSSL signature file location:
http://aix.software.ibm.com/aix/efixes/security/bind_advisory18.asc.sig
https://aix.software.ibm.com/aix/efixes/security/bind_advisory18.asc.sig
ftp://aix.software.ibm.com/aix/efixes/security/bind_advisory18.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
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
Get Notified about Future Security Bulletins
References
Complete CVSS v3 Guide
On-line Calculator v3
Off
AIX Security Bulletin (ASCII format)
Change History
17 Dec 2020: Initial Publication
Document Location
Worldwide
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