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AUSCERT External Security Bulletin Redistribution
Security Bulletin: Vulnerability in Diffie-Hellman ciphers
affects IBM Datapower Gateways (CVE-2015-4000)
11 June 2015
AusCERT Security Bulletin Summary
Product: IBM DataPower Gateways
Operating System: Network Appliance
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
Datapower Gateways (CVE-2015-4000)
More support for:
IBM DataPower Gateways
6.0.0, 6.0.1, 7.0.0, 7.1
The Logjam Attack on TLS connections using the Diffie-Hellman (DH) key
exchange protocol affects IBM Datapower Gateways.
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
All DataPower products and versions that are configured to perform SSL/TLS
transactions as a client.
Workarounds and Mitigations
DataPower appliances acting as an SSL server are not vulnerable.
For appliances acting as an SSL client, disable DH ciphers in DataPower.
To disable the DH ciphers in DataPower, refer to the steps below.
1. Quiesce all domains and services to stop traffic to the appliance. System
quiesce and unquiesce commands can be run by navigating to Administration >
Main > System Control.
2. Select Objects > Crypto Configuration > Crypto Profile in the left
navigation pane. For all the crypto profiles that are configured in the
Configure Crypto Profile page, suffix the existing Ciphers string with a value
:!DH:!kEDH and click Apply.
For example, if you have a default configuration, the updates appears as
Default cipher string: HIGH:MEDIUM:!aNULL:!eNULL:@STRENGTH
DH disabled cipher string: HIGH:MEDIUM:!aNULL:!eNULL:@STRENGTH:!DH:!kEDH
Note that DH must be disabled in all the crypto profiles configured in all the
domains when used in an SSL client profile.
You should verify applying this configuration change does not cause any
Not disabling the DH stream cipher 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 DH stream cipher and take
appropriate mitigation and remediation actions.
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Complete CVSS Guide
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IBM Secure Engineering Web Portal
IBM Product Security Incident Response Blog
Reported to IBM by The WeakDH team at https://weakdh.org
*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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