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AUSCERT External Security Bulletin Redistribution
ESB-2015.1669
Security Bulletin: Vulnerability in Diffie-Hellman ciphers
affects Rational Tau (CVE-2015-4000)
26 June 2015
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AusCERT Security Bulletin Summary
---------------------------------
Product: IBM Rational Tau
Publisher: IBM
Operating System: Linux variants
Windows
Impact/Access: Access Privileged Data -- Remote/Unauthenticated
Provide Misleading Information -- Remote/Unauthenticated
Resolution: Patch/Upgrade
CVE Names: CVE-2015-4000
Reference: ESB-2015.1663
ESB-2015.1655
ESB-2015.1640
ESB-2015.1623
ESB-2015.1614
ESB-2015.1611
ESB-2015.1587
Original Bulletin:
http://www-01.ibm.com/support/docview.wss?uid=swg21960373
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Security Bulletin: Vulnerability in Diffie-Hellman ciphers affects Rational
Tau (CVE-2015-4000)
Document information
More support for:
Rational Tau
Documentation
Software version:
4.3, 4.3.0.1, 4.3.0.2, 4.3.0.3, 4.3.0.4, 4.3.0.5, 4.3.0.6
Operating system(s):
Linux, Windows
Reference #:
1960373
Modified date:
2015-06-25
Security Bulletin
This document applies only to the following language version(s):
English
Summary
The Logjam Attack on TLS connections using the Diffie-Hellman (DH) key
exchange protocol affects Rational Tau
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
4.3, 4.3.0.1, 4.3.0.2, 4.3.0.3, 4.3.0.4, 4.3.0.5, 4.3.0.6, 4.3.0.6 Interim Fix
1, 4.3.0.6 Interim Fix 2, 4.3.0.6 Interim Fix 3
Remediation/Fixes
Upgrade to Rational Tau Interim Fix 4 for 4.3.0.6
Workarounds and Mitigations
No workarounds
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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
19.06.2015: Original version publishe
*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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