Security Bulletin: Vulnerability in Diffie-Hellman ciphers affects Rational Application Developer for WebSphere (CVE-2015-4000)

Summary

The Logjam Attack on TLS connections using the Diffie-Hellman (DH) key exchange protocol affects Rational Application Developer for WebSphere Software

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

Rational Application Developer 9.1.1 and earlier.

Remediation/Fixes

Update the Java Development Kit of the product to address this vulnerability:

• For all versions, apply IBM SDK Java Technology Edition Critical Patch Update - April 2015, RC4 Bar Mitzvah Attack for SSL/TLS, and Logjam vulnerabilities.

• For the WebSphere Application Server 7.0 Test Environment, apply WebSphere Application Server 7.0 Test Environment Extension Fix Pack 37u1 (7.0.0.37u1)

• For WebSphere Application Server version 8.0 and 8.5 used by the product, see Security Bulletin: Vulnerability with Diffie-Hellman ciphers may affect IBM WebSphere Application Server (CVE-2015-4000)
  Rational Agent Controller| 7.0 through to 9.1.1| PI45572|

• Apply Rational Agent Controller FixPack 2 (9.1.1.2) for 9.1.1
  Rational Build Utility| 8.0 through to 9.1.1| PI45572|

• For use on Windows or Linux: apply IBM SDK Java Technology Edition Critical Patch Update - April 2015, RC4 Bar Mitzvah Attack for SSL/TLS, and Logjam vulnerabilities.

• For use on System z:

  • Version 8.0: Apply the latest Java Technology Edition, V6.0.0 PTF.
  • Version 8.5, 9.0 and 9.1: Apply the latest Java Technology Edition, V7.0.0.

Workarounds and Mitigations

None.

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.