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AUSCERT External Security Bulletin Redistribution
Security Bulletin: Vulnerability in Diffie-Hellman ciphers affects IBM
Support Assistant Team Server (CVE-2015-4000)
12 June 2015
AusCERT Security Bulletin Summary
Product: IBM Support Assistant
Operating System: AIX
Impact/Access: Access Privileged Data -- Remote/Unauthenticated
Provide Misleading Information -- Remote/Unauthenticated
CVE Names: CVE-2015-4000
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Security Bulletin: Vulnerability in Diffie-Hellman ciphers affects IBM Support
Assistant Team Server (CVE-2015-4000)
More support for:
IBM Support Assistant
5.0, 18.104.22.168, 22.214.171.124, 126.96.36.199
AIX, Linux, Windows
The Logjam Attack on TLS connections using the Diffie-Hellman (DH) key
exchange protocol affects IBM Support Assistant
DESCRIPTION: The TLS protocol could allow a remote attacker to obtain
sensitive information, caused by the failure to properly convey a DHE_EXPORT
ciphersuite choice. An attacker could exploit this vulnerability using
man-in-the-middle techniques to force a downgrade to 512-bit export-grade
cipher. Successful exploitation could allow an attacker to recover the session
key as well as modify the contents of the traffic. This vulnerability is
commonly referred to as "Logjam".
CVSS Base Score: 4.3
CVSS Temporal Score: See
https://exchange.xforce.ibmcloud.com/vulnerabilities/103294 for the current
CVSS Environmental Score*: Undefined
CVSS Vector: (AV:N/AC:M/Au:N/C:P/I:N/A:N)
Affected Products and Versions
IBM Support Assistant Team Server version 5.0.0, 5.0.1, 188.8.131.52 and 5.0.2
Workarounds and Mitigations
The Logjam attack which affects TLS connections using the Diffie-Hellman (DH)
key exchange protocol may affect the IBM Support Assistant. The IBM WebSphere
Application Server Liberty shipped with IBM Support Assistant has DH and DHE
ciphers included in the "STRONG" or "HIGH", "MEDIUM" and "LOW" cipher lists.
They also could be present if you have a "CUSTOM" list of ciphers. You will
need to remove any of the ciphers that begin with SSL_* or TLS_* that also
have DH or DHE in the Name from your IBM Support Assistant SSL configuration.
This does NOT include ciphers that have ECDH or ECDHE in the Name, these are
elliptic curve Diffie-Hellman ciphers and they are not affected.
To change the list of enabled ciphers:
1. Open a command prompt, then change directory to the
2. Open the server.xml file with a text editor.
3. Add the enabledCiphers attribute with the list of ciphers.
See IBM SDK Cipher suites Knowledge Center for more information on the IBM
SDK Java Technology Edition ciphers that are supported
For additional details on how to change the configuration refer to the
Liberty Profile: SSL Configuration attributes Knowledge Center
Refer to the Security Bulletin for WebSphere Application Server Liberty
Profile for additional details.
You should verify applying this configuration change does not cause any
compatibility issues. Not disabling the DH or DHE stream ciphers will expose
yourself to the Logjam attack described above. IBM recommends that you review
your entire environment to identify other areas where you have enabled the
Diffie-Hellman key-exchange protocol used in TLS and take appropriate
mitigation and remediation actions.
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Complete CVSS Guide
On-line Calculator V2
IBM Secure Engineering Web Portal
IBM Product Security Incident Response Blog
Reported to IBM by The WeakDH team at https://weakdh.org
10 June 2015: original document published
*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.
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.
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