8.1 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
6.9 Medium
CVSS2
Access Vector
LOCAL
Access Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
COMPLETE
Integrity Impact
COMPLETE
Availability Impact
COMPLETE
AV:L/AC:M/Au:N/C:C/I:C/A:C
0.003 Low
EPSS
Percentile
67.3%
IBM SECURITY ADVISORY
First Issued: Fri Jan 29 16:13:16 CST 2016
The most recent version of this document is available here:
http://aix.software.ibm.com/aix/efixes/security/openssh_advisory7.asc
https://aix.software.ibm.com/aix/efixes/security/openssh_advisory7.asc
ftp://aix.software.ibm.com/aix/efixes/security/openssh_advisory7.asc
Security Bulletin: Vulnerabilities in OpenSSH affect AIX (CVE-2016-0777 and
CVE-2016-0778)
===============================================================================
SUMMARY:
An information leak flaw and buffer overflow flaw in the way the OpenSSH
client roaming feature was implemented affects AIX.
===============================================================================
VULNERABILITY DETAILS:
CVEID: CVE-2016-0777
DESCRIPTION: OpenSSH could allow a remote attacker to obtain sensitive
information, caused by a client information leak from using the roaming
connection feature. By persuading a victim to connect to a malicious
server, an attacker could exploit this vulnerability to retrieve
private cryptographic keys or other sensitive information.
CVSS Base Score: 6.5
CVSS Temporal Score: See
https://exchange.xforce.ibmcloud.com/vulnerabilities/109635 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:N/A:N)
CVEID: CVE-2016-0778
DESCRIPTION: OpenSSH is vulnerable to a heap-based buffer overflow, caused
by improper bounds checking by the packet_write_wait() and
ssh_packet_write_wait() API functions when two non-default options: a
ProxyCommand and either ForwardAgent or ForwardX11are used. By
persuading a victim to connect to a malicious server, a remote attacker
could overflow a buffer and execute arbitrary code on the system or
cause the application to crash.
CVSS Base Score: 5
CVSS Temporal Score: See
https://exchange.xforce.ibmcloud.com/vulnerabilities/109636 for the
current score.
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:L)
AFFECTED PRODUCTS AND VERSION:
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
-------------------------------------------------------------
openssh.base.client 4.0.0.5200 6.0.0.6201 key_w_fs
openssh.base.server 4.0.0.5200 6.0.0.6201 key_w_fs
Note: To determine if your system is vulnerable, execute the
following commands:
lslpp -L | grep -i openssh.base.client
lslpp -L | grep -i openssh.base.server
REMEDIATION:
A. FIXES
Fixes are available. The fixes can be downloaded via ftp and
http from:
ftp://aix.software.ibm.com/aix/efixes/security/openssh_fix7.tar
http://aix.software.ibm.com/aix/efixes/security/openssh_fix7.tar
https://aix.software.ibm.com/aix/efixes/security/openssh_fix7.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
releases.
Note that the tar file contains Interim fixes that are based on
OpenSSH version as given below -
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 IV80743m9b.160127.epkg.Z openssh.base(6.0.0.6110 version) key_w_fix
5.3, 6.1, 7.1, 7.2 IV80743m9a.160127.epkg.Z openssh.base(6.0.0.6201 version) key_w_fix
VIOS Level Interim Fix (*.Z) Fileset Name(prereq for installation) KEY
----------------------------------------------------------------------------------------
2.2.* IV80743m9b.160127.epkg.Z openssh.base(6.0.0.6110 version) key_w_fix
2.2.* IV80743m9a.160127.epkg.Z openssh.base(6.0.0.6201 version) key_w_fix
Note - OpenSSH releases 6.0.0.6110 and 6.0.0.6201 are same
except that 6.0.0.6201 is compiled with OpenSSL v1.0.1 and
contains ECDSA key support. Refer to the fileset readme file for
more details.
Latest level of OpenSSH fileset is available from the web download site:
https://www14.software.ibm.com/webapp/iwm/web/reg/download.do?source=aixbp&lang=en_US&S_PKG=openssh&cp=UTF-8
OpenSSH 6.0.0.6201 version is also part of AIX Service pack:
6100-09-06-1543, that was released in Dec. 2015.
To extract the fix from the tar file:
tar xvf openssh_fix7.tar
cd openssh_fix7
Verify you have retrieved the fix intact:
The checksums below were generated using the
"openssl dgst -sha256 file" command is the followng:
openssl dgst -sha256 filename KEY
-----------------------------------------------------------------------------------------------------
f264d388a950bd0c536e7d167541c2578c1c0914163e82e01652f546c7c9fe5a IV80743m9a.160127.epkg.Z key_w_csum
19fa6f702f2644d237fa51dd7ea720ad95e5ca196d6122f97b92693211aa8528 IV80743m9b.160127.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.
Published advisory OpenSSL signature file location:
http://aix.software.ibm.com/aix/efixes/security/openssh_advisory7.asc.sig
https://aix.software.ibm.com/aix/efixes/security/openssh_advisory7.asc.sig
ftp://aix.software.ibm.com/aix/efixes/security/openssh_advisory7.asc.sig
openssl dgst -sha1 -verify <pubkey_file> -signature
<advisory_file>.sig <advisory_file>
openssl dgst -sha1 -verify <pubkey_file> -signature
<ifix_file>.sig <ifix_file>
B. FIX AND INTERIM FIX INSTALLATION
After applying fix, IBM recommends that you regenerate your SSH keys as
a precaution.
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:
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:
Note: Keywords labeled as KEY in this document are used for parsing purposes.
eServer is a trademark of International Business Machines
Corporation. IBM, AIX and pSeries are registered trademarks of
International Business Machines Corporation. All other trademarks
are property of their respective holders.
Complete CVSS v3 Guide: http://www.first.org/cvss/user-guide
On-line Calculator v3:
http://www.first.org/cvss/calculator/3.0
X-Force Vulnerability Database: https://exchange.xforce.ibmcloud.com/vulnerabilities/109636
X-Force Vulnerability Database: https://exchange.xforce.ibmcloud.com/vulnerabilities/109635
CVE-2015-6563 : https://vulners.com/cve/CVE-2016-0777
CVE-2015-6564 : https://vulners.com/cve/CVE-2016-0778
ACKNOWLEDGEMENTS:
None
CHANGE HISTORY:
First Issued: Fri Jan 29 16:13:16 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 Flash.
Note: 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.
8.1 High
CVSS3
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
6.9 Medium
CVSS2
Access Vector
LOCAL
Access Complexity
MEDIUM
Authentication
NONE
Confidentiality Impact
COMPLETE
Integrity Impact
COMPLETE
Availability Impact
COMPLETE
AV:L/AC:M/Au:N/C:C/I:C/A:C
0.003 Low
EPSS
Percentile
67.3%