UPDATED Mar 16 (See Change History - New iFixes Provided): There is a vulnerability in BIND that affects AIX.
CVEID:CVE-2021-25219
**DESCRIPTION:**ISC BIND is vulnerable to a denial of service, caused by a flaw in response processing. By abusing a lame cache, an attacker could exploit this vulnerability to cause a named resolver to spend most of its CPU time on managing and checking the lame cache and severely degrade resolver performance.
CVSS Base score: 5.3
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/212375 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)
Affected Product(s) | Version(s) |
---|---|
AIX | 7.1 |
AIX | 7.2 |
AIX | 7.3 |
VIOS | 3.1 |
The following fileset levels are vulnerable:
Fileset | Lower Level | Upper Level |
---|---|---|
bos.net.tcp.server | 7.1.5.0 | 7.1.5.35 |
bos.net.tcp.client | 7.1.5.0 | 7.1.5.40 |
bos.net.tcp.bind | 7.2.4.0 | 7.2.4.1 |
bos.net.tcp.bind_utils | 7.2.4.0 | 7.2.4.3 |
bos.net.tcp.bind | 7.2.5.0 | 7.2.5.1 |
bos.net.tcp.bind_utils | 7.2.5.0 | 7.2.5.2 |
bos.net.tcp.bind | 7.2.5.100 | 7.2.5.100 |
bos.net.tcp.bind_utils | 7.2.5.100 | 7.2.5.100 |
bos.net.tcp.bind | 7.3.0.0 | 7.3.0.0 |
bos.net.tcp.bind_utils | 7.3.0.0 | 7.3.0.0 |
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
A. APARS
IBM has assigned the following APARs to this problem:
AIX Level | APAR | SP |
---|---|---|
7.1.5 | IJ37222 | SP10 |
7.2.4 | IJ37225 | SP06 |
7.2.5 | IJ37223 | SP04 |
7.3.0 | IJ37226 | SP02 |
VIOS Level | APAR | SP |
---|---|---|
3.1.1 | IJ37225 | 3.1.1.60 |
3.1.2 | IJ37224 | 3.1.2.40 |
3.1.3 | IJ37223 | 3.1.3.20 |
Subscribe to the APARs here:
<https://www.ibm.com/support/pages/apar/IJ37222>
<https://www.ibm.com/support/pages/apar/IJ37223>
<https://www.ibm.com/support/pages/apar/IJ37224>
<https://www.ibm.com/support/pages/apar/IJ37225>
<https://www.ibm.com/support/pages/apar/IJ37226>
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_fix20.tar
<http://aix.software.ibm.com/aix/efixes/security/bind_fix20.tar>
<https://aix.software.ibm.com/aix/efixes/security/bind_fix20.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 |
---|---|
7.1.5.7 | IJ37222m9c.220315.epkg.Z |
7.1.5.8 | IJ37222m9c.220315.epkg.Z |
7.1.5.9 | IJ37222m9c.220315.epkg.Z |
7.2.4.3 | IJ37225m5c.220315.epkg.Z |
7.2.4.4 | IJ37225m5c.220315.epkg.Z |
7.2.4.5 | IJ37225m5c.220315.epkg.Z |
7.2.5.1 | IJ37224m3c.220315.epkg.Z |
7.2.5.2 | IJ37224m3c.220315.epkg.Z |
7.2.5.3 | IJ37224m3c.220315.epkg.Z |
7.3.0.1 | IJ37226s1b.220315.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 |
---|---|
3.1.1.30 | IJ37225m5c.220315.epkg.Z |
3.1.1.40 | IJ37225m5c.220315.epkg.Z |
3.1.1.50 | IJ37225m5c.220315.epkg.Z |
3.1.2.10 | IJ37224m3c.220315.epkg.Z |
3.1.2.21 | IJ37224m3c.220315.epkg.Z |
3.1.3.10 | IJ37224m3c.220315.epkg.Z |
3.1.3.14 | IJ37224m3c.220315.epkg.Z |
The above fixes are cumulative and address previously issued AIX/VIOS BIND security bulletins.
To extract the fixes from the tar file:
tar xvf bind_fix20.tar
cd bind_fix20
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 |
---|---|
c97ca6a6f08834de85adf24854956cb23cc948b5fab83b87ed9314b49fedb97d | IJ37222m9c.220315.epkg.Z |
1b664c2db58503d69141d34e5b11165ce110d7b5150b228c9cd4ba6172094042 | IJ37224m3c.220315.epkg.Z |
d0af2eab502a4ed848326db6d4af6680ad4fa015225cea58aacc807b8ff3b0f8 | IJ37225m5c.220315.epkg.Z |
6dab0239b497eab26d75a2b8cf5715b9d4c74cb10a1ae835b229dbf5037c12c0 | IJ37226s1b.220315.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 -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_advisory20.asc.sig>
<https://aix.software.ibm.com/aix/efixes/security/bind_advisory20.asc.sig>
ftp://aix.software.ibm.com/aix/efixes/security/bind_advisory20.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
To install a fix package:
installp -a -d fix_name -X all # where fix_name is the name of the
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
To install an interim fix package:
emgr -e ipkg_name -X # where ipkg_name is the name of the
None