IBM Support

Security Bulletin:Vulnerability in Diffie-Hellman ciphers affects Rational Build Forge (CVE-2015-4000)

Security Bulletin


Summary

The Logjam Attack on TLS connections using the Diffie-Hellman (DH) key exchange protocol affects Rational Build Forge.

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

BuildForge Versions: 7.1.2, 7.1.2.1, 7.1.2.2, 7.1.2.3, 7.1.3, 7.1.3.1, 7.1.3.2, 7.1.3.3, 7.1.3.4, 7.1.3.5, 7.1.3.6, 8.0, 8.0.0.1, 8.0.0.2.

Remediation/Fixes

Apply the correct fix pack or iFix for your version of Build Forge:

Affected Version Fix
Build Forge 7.1.1.0 - 7.1.1.4 7.1.1.4 iFix (not released yet) or upgrade to 7.1.2.x or 7.1.3.x

Note: If you need 7.1.1.4 iFix contact IBM support
Build Forge 7.1.2.0 - 7.1.2.3 7.1.2.3 iFix 7
Build Forge 7.1.3.0 - 7.1.3.6 7.1.3.6 iFix 6
Build Forge 8.0 - 8.0.0.2 8.0.0.2 iFix 7

Workarounds and Mitigations

Make the following configuration changes to disable DHE and EDH:

Apache
Configure ssl.conf under <buildforge_installpath>/server/apache/conf/ssl/ssl.conf
Add !DHE:!EDH to disable DHE and EDH. Remove any section that explicitly enables DHE or EDH.

For example:
old entry:
SSLCipherSuite ALL:!ADH:!RC4:+HIGH:+MEDIUM:!LOW:!SSLv2:!SSLV3:!EXPORT
new entry (all on one line):
SSLCipherSuite ALL:!ADH:!RC4:+HIGH:+MEDIUM:!LOW:!SSLv2:!SSLV3:!EXPORT:!DHE:!EDH

Agent
Configure bfagent.conf to alter the agent configuration. Add !DHE:!EDH to disable DHE and EDH. Remove any section that explicitly enables DHE or EDH.

For example:
old entry:
ssl_cipher_group ALL
new entry (all on one line):
ssl_cipher_group ALL:!ADH:+HIGH:+MEDIUM:!LOW:!SSLv2:!SSLV3:!EXPORT:!DHE:!EDH

Get Notified about Future Security Bulletins

References

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

*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.

Document information

More support for: Rational Build Forge
Web Console

Software version: 7.1.1.1, 7.1.1.2, 7.1.1.3, 7.1.1.4, 7.1.2, 7.1.2.1, 7.1.2.2, 7.1.2.3, 7.1.3, 7.1.3.1, 7.1.3.2, 7.1.3.3, 7.1.3.4, 7.1.3.5, 7.1.3.6, 8.0, 8.0.0.1, 8.0.0.2

Operating system(s): AIX, HP-UX, Linux, Solaris, Windows, z/OS

Software edition: Enterprise, Enterprise Plus, Standard

Reference #: 1959636

Modified date: 22 June 2015


Translate this page: