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AUSCERT External Security Bulletin Redistribution
Security Bulletin: Vulnerability in Diffie-Hellman ciphers
affects IBM Algo Credit Manager (CVE-2015-4000)
11 June 2015
AusCERT Security Bulletin Summary
Product: IBM Algo Credit Manager
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 Algo
Credit Manager (CVE-2015-4000)
More support for:
Algo Credit Manager
The Logjam Attack on TLS connections using the Diffie-Hellman (DH) key
exchange protocol affects IBM Algo Credit Manager.
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
Algo Credit Manager 5.2.0
Workarounds and Mitigations
To disable DHE cipher suites on your IBM Algo Credit Manager server
$JRT_HOME/platform/<linux64|AIX>/jre/jre/lib/security/java.security. Find the
line jdk.tls.disabledAlgorithms=SSLv3 and change it to
jdk.tls.disabledAlgorithms=SSLv3, RC4, DHE
You should verify applying this configuration change does not cause any
compatibility issues. 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 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 Version 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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