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The Diffie-Hellman vulnerability known as Logjam in Apache Tomcat may affect IBM WebSphere Application Server Community Edition (CVE-2015-4000)

Security Bulletin


Summary

Apache Tomcat which is shipped with WebSphere Application Server Community Edition (WASCE) 3.0.0.4 is vulnerable to Diffie-Hellman vulnerability known as Logjam

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

WebSphere Application Server Community Edition 3.0.0.4

Remediation/Fixes


Tomcat provide a choice for SSL implementation:(refer to
https://tomcat.apache.org/tomcat-7.0-doc/ssl-howto.html)

1. the JSSE implementation provided as part of the Java runtime (since 1.4)
2. the APR implementation, which uses the OpenSSL engine by default.

Per JSSE:
Specify the cipher suites in the server.xml file as below if your JDK is vulnerable to Diffie-Hellman vulnerability known as Logjam :

<Connector
ciphers="TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384,TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,TLS_DHE_RSA_WITH_AES_128_GCM_SHA256,TLS_DHE_DSS_WITH_AES_128_GCM_SHA256,TLS_ECDHE_RSA_WITH_AES_128_SHA256,TLS_ECDHE_ECDSA_WITH_AES_128_SHA256,TLS_ECDHE_RSA_WITH_AES_128_SHA,TLS_ECDHE_ECDSA_WITH_AES_128_SHA,TLS_ECDHE_RSA_WITH_AES_256_SHA384,TLS_ECDHE_ECDSA_WITH_AES_256_SHA384,TLS_ECDHE_RSA_WITH_AES_256_SHA,TLS_ECDHE_ECDSA_WITH_AES_256_SHA,TLS_DHE_RSA_WITH_AES_128_SHA256,TLS_DHE_RSA_WITH_AES_128_SHA,TLS_DHE_DSS_WITH_AES_128_SHA256,TLS_DHE_RSA_WITH_AES_256_SHA256,TLS_DHE_DSS_WITH_AES_256_SHA,TLS_DHE_RSA_WITH_AES_256_SHA"
/>

Per OpenSSL:

Add !DHE:!EDH to disable DHE/EDH and remove any lines that explicitly enable DHE/EDH

i.e. old
SSLCipherSuite ALL:!ADH:!RC4:+HIGH:+MEDIUM:!LOW:!SSLv2:!SSLv3:!EXPORT:DHE:EDH
new
ALL:!ADH:!RC4:+HIGH:+MEDIUM:!LOW:!SSLv2:!SSLv3:!EXPORT:!DHE:!EDH

Check with openssl ciphers -V command to make sure DHE/EDH are disabled. See
http://www.openssl.org/docs/apps/ciphers.html for more detail on the syntax of cipher suite configuration

Get Notified about Future Security Bulletins

References

Related information

Change History

8th 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

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: WebSphere Application Server Community Edition
Tomcat

Software version: 3.0.0.4

Operating system(s): AIX, Linux, Solaris, Windows

Software edition: Elite, Enhanced, Entry

Reference #: 1959539

Modified date: 09 June 2015


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