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
68.4%
IBM SECURITY ADVISORY
First Issued: Wed Sep 28 13:38:50 CDT 2022
The most recent version of this document is available here:
http://aix.software.ibm.com/aix/efixes/security/zlib_advisory.asc
https://aix.software.ibm.com/aix/efixes/security/zlib_advisory.asc
ftp://aix.software.ibm.com/aix/efixes/security/zlib_advisory.asc
Security Bulletin: AIX is vulnerable to denial of service due to zlib
and zlibNX (CVE-2018-25032)
===============================================================================
SUMMARY:
A vulnerability in zlib and zlibNX could allow a remote attacker to cause
a denial of service (CVE-2018-25032). AIX uses zlib and zlibNX as part
of its data compression functions.
===============================================================================
VULNERABILITY DETAILS:
CVEID: CVE-2018-25032
https://vulners.com/cve/CVE-2018-25032
https://vulners.com/cve/CVE-2018-25032
DESCRIPTION: Zlib is vulnerable to a denial of service, caused by a
memory corruption in the deflate operation. By using many distant
matches, a remote attacker could exploit this vulnerability to cause
the application to crash.
CVSS Base Score: 7.5
CVSS Temporal Score: See
https://exchange.xforce.ibmcloud.com/vulnerabilities/222615
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, 7.3
VIOS 3.1
The following fileset levels are vulnerable:
key_fileset = aix
For zlib:
Fileset Lower Level Upper Level KEY PRODUCT(S)
---------------------------------------------------------------------
rpm.rte 4.9.1.3 4.15.1.1005 key_w_fs zlib
rpm.rte 4.15.1.2000 4.15.1.2005 key_w_fs zlib
For zlibNX:
Fileset Lower Level Upper Level KEY PRODUCT(S)
---------------------------------------------------------------------
zlibNX.rte 7.2.4.0 7.2.4.7 key_w_fs zlibNX
zlibNX.rte 7.3.0.0 7.3.0.1 key_w_fs zlibNX
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 zlibNX.rte
REMEDIATION:
A. 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/zlib_fix.tar
http://aix.software.ibm.com/aix/efixes/security/zlib_fix.tar
https://aix.software.ibm.com/aix/efixes/security/zlib_fix.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.
For zlib:
AIX Level Fix KEY PRODUCT(S)
---------------------------------------------------------------
7.1, 7.2 rpm.rte.4.15.1.1006 key_w_fix zlib
7.3 rpm.rte.4.15.1.2006 key_w_fix zlib
VIOS Level Fix KEY PRODUCT(S)
---------------------------------------------------------------
3.1 rpm.rte.4.15.1.1006 key_w_fix zlib
For zlibNX:
AIX Level Interim Fix (*.Z) KEY PRODUCT(S)
----------------------------------------------------------
7.2 IJ41754s4a.220829.epkg.Z key_w_fix zlibNX
7.3 IJ42198s2a.220829.epkg.Z key_w_fix zlibNX
Please reference the Affected Products and Version section above
for help with checking installed fileset levels.
VIOS Level Interim Fix (*.Z) KEY PRODUCT(S)
-----------------------------------------------------------
3.1 IJ41754s4a.220829.epkg.Z key_w_fix zlibNX
To extract the fixes from the tar file:
tar xvf zlib_fix.tar
cd zlib_fix
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
-----------------------------------------------------------------------------------------------------
6e830be2ce0057d12072bef887337b39a5fb97cc6fceafbdf3c9d1c8f6bda8be IJ41754s4a.220829.epkg.Z key_w_csum
91b35e4f334463f49d76e263c70fa8dce09dbc9825d3bb7640b8d186511dfd02 IJ42198s2a.220829.epkg.Z key_w_csum
f12ab2fa1cce9129dc27f2d8a6af1f3e5a1075c93da87ff5f67519d19cfd8db1 rpm.rte.4.15.1.1006 key_w_csum
942c99ecb388645676e3f9361b0157406997188f4249ff7d07ee58bf3271cc34 rpm.rte.4.15.1.2006 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/zlib_advisory.asc.sig
https://aix.software.ibm.com/aix/efixes/security/zlib_advisory.asc.sig
ftp://aix.software.ibm.com/aix/efixes/security/zlib_advisory.asc.sig
B. 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: AIX is vulnerable to denial of service due to zlib
and zlibNX (CVE-2018-25032)
https://www.ibm.com/support/pages/node/6824891
ACKNOWLEDGEMENTS:
None.
CHANGE HISTORY:
First Issued: Wed Sep 28 13:38:50 CDT 2022
===============================================================================
*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
68.4%