Security Bulletin: Vulnerability in Diffie-Hellman ciphers affects IBM Sterling Connect:Direct Browser (CVE-2015-4000)

Summary

The Logjam Attack on TLS connections using the Diffie-Hellman (DH) key exchange protocol affects IBM Sterling Connect:Direct Browser.

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:
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 Sterling Connect:Direct Browser 1.4.0 through 1.4.11
IBM Sterling Connect:Direct Browser 1.5.0 through 1.5.02 iFix10

Remediation/Fixes

None.

Workarounds and Mitigations

Disabling DH and DHE ciphersuites. This 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:

<connect_direct_browser_install>\jre\\lib\security\java.security

jdk.tls.disabledAlgorithms=SSLv3, RC4, DH, DHE

Adding this line to the java.security file will disable features exploited by Poodle, RC4 (Bar Mitzvah), and logjam vulnerabilities.

You should verify applying this configuration change does not cause any compatibility issues. 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.