There is a vulnerability in IBM® SDK Java™ Technology Edition that is used by IBM i. This vulnerability, commonly referred to as “SLOTH”, was disclosed as part of the IBM Java SDK updates in January 2016.
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. This vulnerability is commonly referred to as “SLOTH”.
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
Releases 6.1, 7.1 and 7.2 of IBM i are affected.
The issue can be fixed by applying a PTF to the IBM i Operating System and products.
Please see the Java document at this URL for the latest Java information for IBM i:
Releases 6.1, 7.1 and 7.2 of IBM i are supported and will be fixed.
Release 6.1 & 7.1:
(1) 32bit: SI59364
(2) 64bit: SI59367
(1) 32bit: SI59365
(2) 64bit: SI59366
Release 6.1 & 7.1:
(1) 32bit: SI59369
(2) 64bit: SI59372
(1) 32bit: SI59370
(2) 64bit: SI59371
(1) 32bit: SI59330 SI59336
(2) 64Bit: SI59331 SI59337
(1) 32bit: SI59332
(2) 64bit: SI59333
(1) 32bit: SI59325
(2) 64bit: SI59326
(1) 32bit: SI59327
(2) 64bit: SI59328
(1) 32bit: SI59313
(1) 64Bit: SI59314
(1) 32bit: SI59315
(2) 64bit: SI59316
Important note: IBM recommends that all users running unsupported versions of affected products upgrade to supported and fixed version of affected products.
Workarounds and Mitigations
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.
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Reported to IBM by Karthikeyan Bhargavan at INRIA in Paris, France.
*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.
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.
18 December 2019