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             AUSCERT External Security Bulletin Redistribution

                               ESB-2015.1522
        Security Bulletin: Vulnerability in Diffie-Hellman ciphers
              affects IBM Algo Credit Manager (CVE-2015-4000)
                               11 June 2015

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        AusCERT Security Bulletin Summary
        ---------------------------------

Product:           IBM Algo Credit Manager
Publisher:         IBM
Operating System:  AIX
                   Linux variants
Impact/Access:     Access Privileged Data         -- Remote/Unauthenticated
                   Provide Misleading Information -- Remote/Unauthenticated
Resolution:        Mitigation
CVE Names:         CVE-2015-4000  

Reference:         ESB-2015.1510
                   ESB-2015.1486
                   ESB-2015.1470
                   ESB-2015.1469
                   ESB-2015.1466
                   ESB-2015.1463
                   ESB-2015.1455
                   ESB-2015.1454
                   ESB-2015.1453
                   ESB-2015.1452
                   ESB-2015.1445
                   ESB-2015.1443
                   ESB-2015.1432
                   ESB-2015.1425

Original Bulletin: 
   http://www-01.ibm.com/support/docview.wss?uid=swg21959628

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Security Bulletin: Vulnerability in Diffie-Hellman ciphers affects IBM Algo 
Credit Manager (CVE-2015-4000)

Security Bulletin

Document information

More support for:

Algo Credit Manager

Software version:

5.2

Operating system(s):

AIX, Linux

Reference #:

1959628

Modified date:

2015-06-10

Summary

The Logjam Attack on TLS connections using the Diffie-Hellman (DH) key 
exchange protocol affects IBM Algo Credit Manager.

Vulnerability Details

CVEID: CVE-2015-4000

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 
score

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

Remediation/Fixes

None

Workarounds and Mitigations

To disable DHE cipher suites on your IBM Algo Credit Manager server 
installation, edit 
$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.

Get Notified about Future Security Bulletins

Subscribe to My Notifications to be notified of important product support 
alerts like this.

References

Complete CVSS Guide

On-line Calculator V2

Related information

IBM Secure Engineering Web Portal

IBM Product Security Incident Response Blog

Acknowledgement

Reported to IBM by The WeakDH team at https://weakdh.org

Change History

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.

Disclaimer

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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