Security Bulletin: Vulnerability in Diffie-Hellman ciphers affects IBM Cognos Business Intelligence (CVE-2015-4000)

Summary

The Logjam Attack on TLS connections using the Diffie-Hellman (DH) key exchange protocol affects IBM Cognos Business Intelligence

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

IBM Cognos Business Intelligence Server 10.2.2
IBM Cognos Business Intelligence Server 10.2.1.1
IBM Cognos Business Intelligence Server 10.2
IBM Cognos Business Intelligence Server 10.1.1
IBM Cognos Business Intelligence Server 10.1
IBM Cognos Business Intelligence Server 8.4.1

Remediation/Fixes

None

Workarounds and Mitigations

The DH cipher suites must be disabled using Cognos Configuration by performing the following actions:

1. Start Cognos Configuration.

2. Navigate to Security/Cryptography/Cognos

3. Open the supported cipher suites selection dialog.

4. Select all cipher suites that have DH in the the name and remove them from the Current Values List. Select OK to save the new list.

5. Save and restart your service using Cognos Configuration.

You should verify applying this configuration change does not cause any compatibility issues. Not disabling the DH stream cipher 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 DH stream cipher and take appropriate mitigation and remediation actions.