5.9 Medium
CVSS3
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
4.3 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:M/Au:N/C:N/I:P/A:N
0.003 Low
EPSS
Percentile
68.5%
IBM SECURITY ADVISORY
First Issued: Fri Jan 29 15:43:20 CST 2016
The most recent version of this document is available here:
http://aix.software.ibm.com/aix/efixes/security/openssl_advisory16.asc
https://aix.software.ibm.com/aix/efixes/security/openssl_advisory16.asc
ftp://aix.software.ibm.com/aix/efixes/security/openssl_advisory16.asc
Security Bulletin: Vulnerability in MD5 Signature and Hash Algorithm affects
OpenSSL on AIX (CVE-2015-7575)
===============================================================================
SUMMARY:
The MD5 �SLOTH� vulnerability on TLS 1.2 affects OpenSSL on AIX.
===============================================================================
VULNERABILITY DETAILS:
CVEID: CVE-2015-7575
DESCRIPTION: The TLS protocol could allow weaker than expected security
caused by a collision attack when using the MD5 hash function for
signing a ServerKeyExchange message during a TLS handshake. An attacker
could exploit this vulnerability using man-in-the-middle techniques to
impersonate a TLS server and obtain credentials.
CVSS Base Score: 7.1
CVSS Temporal Score: See
https://exchange.xforce.ibmcloud.com/vulnerabilities/109415 for the
current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N)
AFFECTED PRODUCTS AND VERSIONS:
AIX 5.3, 6.1, 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 1.0.1.500 1.0.1.515 key_w_fs
Note: 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 openssl.base
REMEDIATION:
A. FIXES
Fixes are available.
The fixes can be downloaded via ftp or http from:
ftp://aix.software.ibm.com/aix/efixes/security/openssl_fix16.tar
http://aix.software.ibm.com/aix/efixes/security/openssl_fix16.tar
https://aix.software.ibm.com/aix/efixes/security/openssl_fix16.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.
Note that the tar file contains Interim fixes that are based on
OpenSSL version.
AIX Level Interim Fix (*.Z) Fileset Name(prereq for installation) KEY
--------------------------------------------------------------------------------------------
5.3, 6.1, 7.1, 7.2 101a_fix.160129.epkg.Z openssl.base(1.0.1.515 version) key_w_fix
VIOS Level Interim Fix (*.Z) Fileset Name(prereq for installation) KEY
--------------------------------------------------------------------------------------------
2.2.* 101a_fix.160129.epkg.Z openssl.base(1.0.1.515 version) key_w_fix
You should verify applying this fix does not cause any
compatibility issues. The fix disables MD5 signature hash by
default. If you change the default setting after applying the fix,
you will expose yourself to the attack described above. IBM
recommends that you review your entire environment to identify
other areas where you have enabled the MD5 signature hash and take
appropriate mitigation and remediation actions.
To extract the fixes from the tar file:
tar xvf openssl_fix16.tar
cd openssl_fix16
Verify you have retrieved the fixes intact:
The checksums below were generated using the
"openssl dgst -sha256 file" command as the followng:
openssl dgst -sha256 filename KEY
----------------------------------------------------------------------------------------------------
bfc26950a361720c2a3692e7dd7f5ae13f782f419b634c34fc42add5b4e83724 101a_fix.160129.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 Security at
[email protected] 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_advisory16.asc.sig
https://aix.software.ibm.com/aix/efixes/security/openssl_advisory16.asc.sig
ftp://aix.software.ibm.com/aix/efixes/security/openssl_advisory16.asc.sig
B. FIX AND INTERIM FIX INSTALLATION
IMPORTANT: 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
Comments regarding the content of this announcement can be
directed to:
[email protected]
To obtain the OpenSSL public key that can be used to verify the
signed advisories and ifixes:
Download the key from our web page:
http://www.ibm.com/systems/resources/systems_p_os_aix_security_pubkey.txt
To obtain the PGP public key that can be used to communicate
securely with the AIX Security Team via [email protected] you
can either:
A. Download the key from our web page:
http://www.ibm.com/systems/resources/systems_p_os_aix_security_pgppubkey.txt
B. Download the key from a PGP Public Key Server. The key ID is:
0x28BFAA12
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
ACKNOWLEDGEMENTS:
Reported to IBM by Karthikeyan Bhargavan at INRIA in Paris, France.
CHANGE HISTORY:
First Issued: Fri Jan 29 15:43:20 CST 2016
===============================================================================
*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.
5.9 Medium
CVSS3
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
NONE
Availability Impact
NONE
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
4.3 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:M/Au:N/C:N/I:P/A:N
0.003 Low
EPSS
Percentile
68.5%