CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:N/I:N/A:P
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
Percentile
93.9%
IBM SECURITY ADVISORY
First Issued: Thu Jul 29 15:13:19 CDT 2021
The most recent version of this document is available here:
http://aix.software.ibm.com/aix/efixes/security/bind_advisory19.asc
https://aix.software.ibm.com/aix/efixes/security/bind_advisory19.asc
ftp://aix.software.ibm.com/aix/efixes/security/bind_advisory19.asc
Security Bulletin: Vulnerability in BIND affects AIX (CVE-2021-25215)
===============================================================================
SUMMARY:
There is a vulnerability in BIND that affects AIX.
===============================================================================
VULNERABILITY DETAILS:
CVEID: CVE-2021-25215
https://vulners.com/cve/CVE-2021-25215
https://vulners.com/cve/CVE-2021-25215
DESCRIPTION: ISC BIND is vulnerable to a denial of service, caused by an
assertion failure while answering queries for DNAME records. By
sending a query for DNAME records, an attacker could exploit this
vulnerability to trigger a failed assertion check and terminate the
named process.
CVSS Base Score: 7.5
CVSS Temporal Score: See
https://exchange.xforce.ibmcloud.com/vulnerabilities/200960
for the current score
CVSS Environmental Score*: Undefined
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:
AIX 7.1, 7.2
VIOS 3.1
The following fileset levels are vulnerable:
key_fileset = aix
Fileset Lower Level Upper Level KEY
---------------------------------------------------------
bos.net.tcp.server 7.1.5.0 7.1.5.34 key_w_fs
bos.net.tcp.bind 7.2.3.0 7.2.3.15 key_w_fs
bos.net.tcp.bind 7.2.4.0 7.2.4.0 key_w_fs
bos.net.tcp.bind 7.2.5.0 7.2.5.1 key_w_fs
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.server
REMEDIATION:
A. APARS
IBM has assigned the following APARs to this problem:
AIX Level APAR Availability SP KEY
-----------------------------------------------------
7.1.5 IJ33276 ** SP09 key_w_apar
7.2.3 IJ33277 ** N/A key_w_apar
7.2.4 IJ33278 ** SP05 key_w_apar
7.2.5 IJ33280 ** SP03 key_w_apar
VIOS Level APAR Availability SP KEY
-----------------------------------------------------
3.1.0 IJ33277 ** N/A key_w_apar
3.1.1 IJ33278 ** 3.1.1.50 key_w_apar
3.1.2 IJ33279 ** 3.1.2.30 key_w_apar
Subscribe to the APARs here:
http://www.ibm.com/support/pages/apar/IJ33276
http://www.ibm.com/support/pages/apar/IJ33277
http://www.ibm.com/support/pages/apar/IJ33278
http://www.ibm.com/support/pages/apar/IJ33279
http://www.ibm.com/support/pages/apar/IJ33280
https://www.ibm.com/support/pages/apar/IJ33276
https://www.ibm.com/support/pages/apar/IJ33277
https://www.ibm.com/support/pages/apar/IJ33278
https://www.ibm.com/support/pages/apar/IJ33279
https://www.ibm.com/support/pages/apar/IJ33280
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_fix19.tar
http://aix.software.ibm.com/aix/efixes/security/bind_fix19.tar
https://aix.software.ibm.com/aix/efixes/security/bind_fix19.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 (*.Z) KEY
----------------------------------------------
7.1.5.6 IJ33276s8a.210622.epkg.Z key_w_fix
7.1.5.7 IJ33276s8a.210622.epkg.Z key_w_fix
7.1.5.8 IJ33276s8a.210622.epkg.Z key_w_fix
7.2.3.5 IJ33277s7a.210622.epkg.Z key_w_fix
7.2.3.6 IJ33277s7a.210622.epkg.Z key_w_fix
7.2.3.7 IJ33277s7a.210622.epkg.Z key_w_fix
7.2.4.2 IJ33278s4a.210622.epkg.Z key_w_fix
7.2.4.3 IJ33278s4a.210622.epkg.Z key_w_fix
7.2.4.4 IJ33278s4a.210622.epkg.Z key_w_fix
7.2.5.0 IJ33279s2a.210621.epkg.Z key_w_fix
7.2.5.1 IJ33279s2a.210621.epkg.Z key_w_fix
7.2.5.2 IJ33279s2a.210621.epkg.Z key_w_fix
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 (*.Z) KEY
-----------------------------------------------
3.1.0.40 IJ33277s7a.210622.epkg.Z key_w_fix
3.1.0.50 IJ33277s7a.210622.epkg.Z key_w_fix
3.1.0.60 IJ33277s7a.210622.epkg.Z key_w_fix
3.1.1.20 IJ33278s4a.210622.epkg.Z key_w_fix
3.1.1.21 IJ33278s4a.210622.epkg.Z key_w_fix
3.1.1.22 IJ33278s4a.210622.epkg.Z key_w_fix
3.1.1.25 IJ33278s4a.210622.epkg.Z key_w_fix
3.1.1.30 IJ33278s4a.210622.epkg.Z key_w_fix
3.1.1.40 IJ33278s4a.210622.epkg.Z key_w_fix
3.1.2.0 IJ33279s2a.210621.epkg.Z key_w_fix
3.1.2.10 IJ33279s2a.210621.epkg.Z key_w_fix
3.1.2.20 IJ33279s2a.210621.epkg.Z key_w_fix
3.1.2.21 IJ33279s2a.210621.epkg.Z key_w_fix
The above fixes are cumulative and address previously issued
AIX/VIOS BIND security bulletins with respect to
/usr/sbin/named9. For full AIX/VIOS BIND remediation,
the above fixes should be installed alongside the fixes
issued with:
https://aix.software.ibm.com/aix/efixes/security/bind_advisory18.asc
https://www.ibm.com/support/pages/node/6388720
To extract the fixes from the tar file:
tar xvf bind_fix19.tar
cd bind_fix19
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 KEY
-----------------------------------------------------------------------------------------------------
702bbfdaddeaa2a4b1e83be581ce1e07a98de4d26754efa3abf6b409430f542e IJ33276s8a.210622.epkg.Z key_w_csum
b54833729d51873682abf944dccb8ff79e67014efe6201f8703cf8dd389211f3 IJ33277s7a.210622.epkg.Z key_w_csum
63c2884898cf1c01ad3b0ff5f19120724e326cc9fa53020f51968f254f719c51 IJ33278s4a.210622.epkg.Z key_w_csum
eacc45c120db7565be64808c7c9a29873a115837ff6863e6533646ac00a0e773 IJ33279s2a.210621.epkg.Z key_w_csum
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 -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/bind_advisory19.asc.sig
https://aix.software.ibm.com/aix/efixes/security/bind_advisory19.asc.sig
ftp://aix.software.ibm.com/aix/efixes/security/bind_advisory19.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.
===============================================================================
CONTACT US:
Note: Keywords labeled as KEY in this document are used for parsing
purposes.
If you would like to receive AIX Security Advisories via email,
please visit "My Notifications":
http://www.ibm.com/support/mynotifications
To view previously issued advisories, please visit:
http://www14.software.ibm.com/webapp/set2/subscriptions/onvdq
Contact IBM Support for questions related to this announcement:
http://ibm.com/support/
https://ibm.com/support/
To obtain the OpenSSL public key that can be used to verify the
signed advisories and ifixes:
Download the key from our web page:
ftp://ftp.software.ibm.com/systems/power/AIX/systems_p_os_aix_security_pubkey.txt
Please contact your local IBM AIX support center for any
assistance.
REFERENCES:
Complete CVSS v3 Guide: http://www.first.org/cvss/user-guide
On-line Calculator v3:
http://www.first.org/cvss/calculator/3.0
RELATED INFORMATION:
IBM Secure Engineering Web Portal
http://www.ibm.com/security/secure-engineering/bulletins.html
IBM Product Security Incident Response Blog
https://www.ibm.com/blogs/psirt/
Security Bulletin: Vulnerability in BIND affects AIX (CVE-2021-25215)
https://www.ibm.com/support/pages/node/6476802
ACKNOWLEDGEMENTS:
None.
CHANGE HISTORY:
First Issued: Thu Jul 29 15:13:19 CDT 2021
===============================================================================
*The CVSS Environment Score is customer environment specific and will
ultimately impact the Overall CVSS Score. Customers can evaluate the impact
of this vulnerability in their environments by accessing the links in the
Reference section of this Security Bulletin.
Disclaimer
According to the Forum of Incident Response and Security Teams (FIRST), the
Common Vulnerability Scoring System (CVSS) is an “industry open standard
designed to convey vulnerability severity and help to determine urgency and
priority of response.” IBM PROVIDES THE CVSS SCORES “AS IS” WITHOUT WARRANTY
OF ANY KIND, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
FOR A PARTICULAR PURPOSE. CUSTOMERS ARE RESPONSIBLE FOR ASSESSING THE IMPACT
OF ANY ACTUAL OR POTENTIAL SECURITY VULNERABILITY.
CVSS2
Attack Vector
NETWORK
Attack Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
PARTIAL
AV:N/AC:L/Au:N/C:N/I:N/A:P
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
Percentile
93.9%