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Security Bulletin: Vulnerability in OpenSSL affects AIX (CVE-2019-1559)

Security Bulletin


Summary

There is a vulnerability in OpenSSL used by AIX.

Vulnerability Details

CVEID: CVE-2019-1559
DESCRIPTION: OpenSSL could allow a remote attacker to obtain sensitive information, caused by the failure to immediately close the TCP connection after the hosts encounter a zero-length record with valid padding. An attacker could exploit this vulnerability using a 0-byte record padding-oracle attack to decrypt traffic.
CVSS Base Score: 5.8
CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/157514 for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N)

Affected Products and Versions

AIX 7.1, 7.2
VIOS 2.2.x

The following fileset levels are vulnerable:
        
key_fileset = osrcaix
Fileset          Lower Level   Upper Level    KEY
------------------------------------------------------
openssl.base    1.0.2.500      1.0.2.1601     key_w_fs
openssl.base    20.13.102.1000 20.16.102.1600 key_w_fs

Note:
A. 0.9.8, 1.0.1 OpenSSL versions are out-of-support. Customers are advised to upgrade to currently supported OpenSSL 1.0.2 version.
B. Latest level of OpenSSL fileset is available from the web download site:
    https://www-01.ibm.com/marketing/iwm/iwm/web/pickUrxNew.do?source=aixbp&S_PKG=openssl
 
To find out whether the affected filesets are installed on your systems, refer to the lslpp command found in the AIX user's guide.

Example:  lslpp -L | grep -i openssl.base

Remediation/Fixes

A. FIXES

The fixes can be downloaded via ftp or http from:
ftp://aix.software.ibm.com/aix/efixes/security/openssl_fix30.tar
http://aix.software.ibm.com/aix/efixes/security/openssl_fix30.tar
https://aix.software.ibm.com/aix/efixes/security/openssl_fix30.tar

The links above are 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.
            
Note that the tar file contains Interim fixes that are based on OpenSSL version, and AIX OpenSSL fixes are cumulative. You must be on the 'prereq for installation' level before applying the interim fix. This may require installing a new level(prereq version) first.

AIX Level           Interim Fix (*.Z)        Fileset Name(prereq for installation) KEY
--------------------------------------------------------------------------------------------
5.3, 6.1, 7.1, 7.2  102pa_mfix.190318.epkg.Z openssl.base(1.0.2.1601)              key_w_fix
5.3, 6.1, 7.1, 7.2  fips_102pa.190318.epkg.Z openssl.base(20.16.102.1600)          key_w_fix

VIOS Level     Interim Fix (*.Z)             Fileset Name(prereq for installation) KEY
--------------------------------------------------------------------------------------------
2.2.x          102pa_mfix.190318.epkg.Z      openssl.base(1.0.2.1601)              key_w_fix
2.2.x          fips_102pa.190318.epkg.Z      openssl.base(20.16.102.1600)          key_w_fix

To extract the fixes from the tar file:
tar xvf openssl_fix30.tar
cd openssl_fix30

Verify you have retrieved the fixes intact:
The checksums below were generated using the "openssl dgst -sha256 file" command as the following:

openssl dgst -sha256                                              filename                 KEY
-----------------------------------------------------------------------------------------------------
cf3418b3cb99e678c47e334460782e4e4eef0a67a32b10612cd4709006ebf4e0  102pa_mfix.190318.epkg.Z key_w_csum
4de4c7534856d1192cf7f80bb5ca0bef8a8b514f78afffbcdf8397959f55163e  fips_102pa.190318.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 AIX Support at https://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/openssl_advisory30.asc.sig
            https://aix.software.ibm.com/aix/efixes/security/openssl_advisory30.asc.sig
            ftp://aix.software.ibm.com/aix/efixes/security/openssl_advisory30.asc.sig

B. FIX AND INTERIM FIX INSTALLATION

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

Reference

Complete CVSS v3 Guide
On-line Calculator v3

Related Information

IBM Secure Engineering Web Portal
IBM Product Security Incident Response Blog

Acknowledgement

None.

*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.

Document information

More support for: AIX family

Software version: 7.1, 7.2

Operating system(s): AIX

Reference #: 0878172

Modified date: 16 April 2019