Security Bulletin: Vulnerability in MD5 Signature and Hash Algorithm affects Rational Performance Tester (CVE-2015-7575)

Summary

The MD5 “SLOTH” vulnerability on TLS 1.2 affects Rational Performance Tester.

Vulnerability Details

CVEID: CVE-2015-7575**
DESCRIPTION:** The TLS protocol could allow weaker than expected security caused by a collision attack when using the MD5 hash function for signing a ServerKeyExchange message during a TLS handshake. An attacker could exploit this vulnerability using man-in-the-middle techniques to impersonate a TLS server and obtain credentials.
CVSS Base Score: 7.1
CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/109415 for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:L/A:N)

Affected Products and Versions

Rational Performance Tester version 8.2., 8.3., 8.5., 8.6. and 8.7.*.

Remediation/Fixes

It is strongly recommened to upgrade to version 9.0 which contains the fix for Bouncy Castle.

Customers affected by Java should continue to use the mitigating steps below until a fix is delivered for Java in version 9.0.0.1.

Workarounds and Mitigations

Mitigating steps for Bouncy Castle:

1. Download the bouncy castle version 1.5.3 ( the jar can be downloaded here https://www.bouncycastle.org/download/jce-jdk13-154.jar ).
2. Locate the previous bouncy castle librarie delivered, this will be typically at the following path:
   INSTALLATION_DIRECTORY/IBM_SHARED_PLUGINS/plugins/com.ibm.rational.ttt.common.models.core_plugin_version/lib/approvedbouncy
   For example::
   C:\Program Files\IBM\IBMIMSharedRPT8702\plugins\com.ibm.rational.ttt.common.models.core_8.5.210.v20150622_1524\lib\approvedbouncy
   for RPT v8.7.0.2.
3. Rename the bouncy castle jar version 1.5.3 downloaded to the name of the previous delivered jar ( jce-jdk13-134.jar ).
4. Replace the old jar with the new one.

For Java disable support for MD5 and MD5with RSA. Mitigating steps involve editing the java.security file under the RPT product installation folder:
Update java.security file:

1. Add MD5 to jdk.certpath.disabledAlgorithms. For example,
   certpath.disabledAlgorithms=MD2, RSA keySize < 1024,MD5
2. Add MD5withRSA to jdk.tls.disabledAlgorithms. For example,
   jdk.tls.disabledAlgorithms=SSLv3, RC4, DH keySize < 768,MD5withRSA

You should verify applying this configuration change does not cause any compatibility issues. Not disabling the MD5 signature hash 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 MD5 signature hash and take appropriate mitigation and remediation actions.