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AUSCERT External Security Bulletin Redistribution
ESB-2015.1830
Security Bulletin: Vulnerability in Diffie-Hellman ciphers
affects Rational DOORS Web Access (CVE-2015-4000)
10 July 2015
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AusCERT Security Bulletin Summary
---------------------------------
Product: IBM Rational DOORS Web Access
Publisher: IBM
Operating System: Windows
Impact/Access: Access Privileged Data -- Remote/Unauthenticated
Provide Misleading Information -- Remote/Unauthenticated
Resolution: Patch/Upgrade
CVE Names: CVE-2015-4000
Reference: ASB-2015.0066
ESB-2015.1824
ESB-2015.1823
ESB-2015.1809
ESB-2015.1799
ESB-2015.1788
ESB-2015.1787
ESB-2015.1782
ESB-2015.1773
Original Bulletin:
http://www-01.ibm.com/support/docview.wss?uid=swg21959696
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Security Bulletin: Vulnerability in Diffie-Hellman ciphers affects Rational
DOORS Web Access (CVE-2015-4000)
Document information
More support for:
Rational DOORS Web Access
General Information
Software version:
1.4, 1.4.0.1, 1.4.0.2, 1.4.0.3, 1.4.0.4, 1.4.0.5, 1.5, 1.5.0.1, 9.5, 9.5.0.1,
9.5.1, 9.5.1.1, 9.5.2, 9.5.2.1, 9.6, 9.6.0.1, 9.6.1, 9.6.1.1, 9.6.1.3
Operating system(s):
Windows
Reference #:
1959696
Modified date:
2015-07-09
Security Bulletin
Summary
The Logjam Attack on TLS connections using the Diffie-Hellman (DH) key
exchange protocol affects IBM Rational DOORS Web Access.
Vulnerability Details
Rational DOORS Web Access is affected by the following vulnerability:
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
Rational DOORS Web Access version 9.6.1.3, 9.6.1.2, 9.6.1.1, 9.6.1.0, 9.6.0.x,
9.5.2.x, 9.5.1.x, 9.5.0.x, 1.5.0.x, 1.4.0.x.
Remediation/Fixes
Prior to the upgrade described below, there is no mitigation if any of the
EXPORT ciphers have been enabled. EXPORT cipher suites are vulnerable to the
FREAK and LOGJAM vulnerabilities with no mitigation possible. Do not enable
these ciphers without complete understanding of the environment.
For all others, consider implementing one of the mitigation methods described
below.
Java 6 Mitigation:
For Rational DOORS Web Access installations that include JRE version 6,
upgrade the JRE as noted in the table below. You can upgrade the JRE after
Rational DOORS Web Access is installed.
To obtain the updated version of the IBM JRE, contact IBM Support. Support can
help identify the latest JRE that is compatible with your operating system and
platform. Publicly available versions of the Oracle JRE are not supported with
Rational DOORS Web Access.
The following table presents Rational DOORS Web Access versions and the
compatible versions of IBM JRE.
Rational DOORS Web Access IBM JRE
1.4.0.x 6.0.16.5
1.5.0.x 6.0.16.5
9.5.0.x 6.0.16.5
9.5.1.x 6.0.16.5
9.5.2.x 6.0.16.5
9.6.0.x See "Workarounds and Mitigations"
9.6.1.x See "Workarounds and Mitigations"For versions for Rational DOORS Web
Access that are earlier than version 1.4.0.x, IBM recommends upgrading to a
fixed, supported version/release/platform of the product.
To install the updated JRE in Rational DOORS Web Access, see this help topic:
Upgrading the Rational DOORS Web Access JRE
You should verify that 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.
Workarounds and Mitigations
Java 7 and Java 8 Mitigation:
For Rational DOORS Web Access installations that include JRE version 7 or 8,
perform the following mitigations.
Disable DH and DHE cipher suites. The can be achieved by adding the DH and DHE
cipher suites to the list of disabled algorithms defined by the
jdk.tls.disabledAlgorithms security property in java.security file.
Do not explicitly enable the DH or DHE cipher suite(s) via
setEnabledCipherSuites() method.
For HttpsURLConnection, set https.cipherSuites system property to not include
DH or DHE cipher suites.
Configure SP800-131a strict compliance or any Suite B configuration.
For those which use JVM defaults or the default list of ciphers provided by
the JVM, apply the iFix which will enforce a minimum 768 bit prime size for DH
and DHE cipher suites and resolve the problem.
For Java the DH server keysize is 1024 unless SP800-131a strict compliance or
Suite B compliance is configured. For those configurations, the server keysize
is 2048. On Java 8 this is configurable. At this time, this is not
configurable for Java 5, 6, and 7.
As the length of the server key size are increased, the amount of CPU required
for full TLS/SSL handshake can significantly increase. Please carefully test
and assess the impact to your CPU requirements to ensure sufficient CPU
resources, otherwise the system availability may be impacted.
You should verify that 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
*9 July 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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