Security Bulletin
Summary
The LogJam Attack on Diffie-Hellman ciphers (CVE-2015-4000) may affect some configurations of Liberty for Java for IBM Bluemix.
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
This vulnerability affects all versions of Liberty for Java in IBM Bluemix up to and including v1.19-20150608-1717.
Remediation/Fixes
To upgrade to Liberty for Java v1.19.1-20150622-1509 or higher, you must re-stage or re-push your application. To check which version of the Liberty for Java runtime your Bluemix application is using, navigate to the "Files and Logs" for your application through the Bluemix UI. In the "logs" directory, check the "staging_task.log".
You can also find this file through the command-line Cloud Foundry client by running the following command:
cf files <appname> logs/staging_task.log
You can see
-----> Liberty Buildpack Version: _________
To re-stage your application using the command-line Cloud Foundry client, use the following command:
cf restage <appname>
To re-push your application using the command-line Cloud Foundry client, use the following command:
cf push <appname>
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References
Change History
30 June 2015: Original document 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
Review the IBM security bulletin disclaimer and definitions regarding your responsibilities for assessing potential impact of security vulnerabilities to your environment.
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Document Information
Modified date:
15 June 2018
UID
swg21961390