5.3 Medium
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
LOW
Availability Impact
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
5 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:L/Au:N/C:N/I:P/A:N
0.007 Low
EPSS
Percentile
79.1%
IBM SECURITY ADVISORY
First Issued: Tue Nov 14 09:46:19 CST 2017
The most recent version of this document is available here:
http://aix.software.ibm.com/aix/efixes/security/openssh_advisory11.asc
https://aix.software.ibm.com/aix/efixes/security/openssh_advisory11.asc
ftp://aix.software.ibm.com/aix/efixes/security/openssh_advisory11.asc
Security Bulletin: Vulnerability in OpenSSH affects AIX (CVE-2017-15906)
===============================================================================
SUMMARY:
Vulnerability in OpenSSH affects AIX.
===============================================================================
VULNERABILITY DETAILS:
CVEID: CVE-2017-15906
https://vulners.com/cve/CVE-2017-15906
https://vulners.com/cve/CVE-2017-15906
DESCRIPTION: The process_open function in sftp-server.c in OpenSSH does
not properly prevent write operations in readonly mode, which allows
attackers to create zero-length files.
CVSS Base Score: 6.5
CVSS Temporal Score: See
https://exchange.xforce.ibmcloud.com/vulnerabilities/133128 for the
current score.
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
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 7.1.102.1100 key_w_fs
openssh.base.server 4.0.0.5200 7.1.102.1100 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:
FIXES
A fix is available, and it can be downloaded from
https://www-01.ibm.com/marketing/iwm/iwm/web/reg/download.do?source=aixbp&lang=en_US&S_PKG=openssh&cp=UTF-8
To extract the fixes from the tar file:
For Openssh 7.5 version -
zcat openssh-7.5.102.1100.tar.Z | tar xvf
Please refer to the Readme file to be aware of the changes that
are part of the release.
IMPORTANT: If possible, it is recommended that a mksysb backup
of the system be created. Verify it is both bootable and
readable before proceeding.
Note that all the previously reported security vulnerability fixes
are also included in above mentioned fileset level. Please refer
to the readme file (provided along with the fileset) for the
complete list of vulnerabilities fixed.
To preview the fix installation:
installp -apYd . openssh
To install the fix package:
installp -aXYd . openssh
Published advisory OpenSSH signature file location:
http://aix.software.ibm.com/aix/efixes/security/openssh_advisory11.asc.sig
https://aix.software.ibm.com/aix/efixes/security/openssh_advisory11.asc.sig
ftp://aix.software.ibm.com/aix/efixes/security/openssh_advisory11.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]
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
https://www.ibm.com/support/mynotifications
To view previously issued advisories, please visit:
http://www14.software.ibm.com/webapp/set2/subscriptions/onvdq
https://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:
http://www.ibm.com/systems/resources/systems_p_os_aix_security_pubkey.txt
https://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
https://www.first.org/cvss/user-guide
On-line Calculator v3:
http://www.first.org/cvss/calculator/3.0
https://www.first.org/cvss/calculator/3.0
ACKNOWLEDGEMENTS:
None
CHANGE HISTORY:
First Issued: Tue Nov 14 09:46:19 CST 2017
===============================================================================
*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.
5.3 Medium
CVSS3
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
LOW
Availability Impact
NONE
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
5 Medium
CVSS2
Access Vector
NETWORK
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
NONE
Integrity Impact
PARTIAL
Availability Impact
NONE
AV:N/AC:L/Au:N/C:N/I:P/A:N
0.007 Low
EPSS
Percentile
79.1%