Security Bulletin
Summary
The LogJam Attack on Diffie-Hellman ciphers (CVE-2015-4000) affects some configurations of IBM Security Key lifecycle Manager.
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
The following IBM Security Key Lifecycle Manager versions may be affected.
· IBM Tivoli Key Lifecycle Manager V1.0, V2.0, V.2.0.1
· IBM Security Key Lifecycle Manager V2.5 on distributed platforms
Remediation/Fixes
Product | VRMF | APAR | Remediation/First Fix |
TKLM | 1.0 | IV74817 | 1.0.0-TIV-TKLM-FP0008 |
TKLM | 2.0 | IV74818 | 2.0.0-ISS-TKLM-FP0010 |
TKLM | 2.0.1 | IV74819 | 2.0.1-ISS-TKLM-FP0008 |
SKLM | 2.5 | IV74820 | 2.5.0-ISS-SKLM-FP0006 |
Workarounds and Mitigations
There are multiple workaround cases:
Case 1: TKLM/SKLM configuration file has the TransportListener.ssl.ciphersuites property set with DHE or DH cipher suites.
Workaround: Remove DHE and DH ciphers and set only non-DH ciphers in this property. If only one cipher is mentioned which is DHE or DH and user is unsure about which ciphers to use then comment out this property or specify JSSE_ALL and move to Case 2.
Case 2: TKLM/SKLM configuration file does not have the TransportListener.ssl.ciphersuites property specified or TransportListener.ssl.ciphersuites property is set to a value of JSSE_ALL.
Workaround: Specify this property with non-DH ciphers or create a custom Cipher suite group with no DHE and DH ciphers by logging into Websphere Application Server. Users can create custom cipher suites in the WAS console UI from SSL certificate and key management > SSL configurations > NodeDefaultSSLSettings > Quality of protection (QoP) settings
Case 3: TKLM/SKLM configuration file has the TransportListener.ssl.ciphersuites property set to cipher suites which does not include DHE and DH cipher suites
Workaround: Users are safe from this vulnerability and nothing needs to be done.
Name of TKLM/SKLM config file for TKLM v1.x to v2.0.x is TKLMgrConfig.properties and for SKLM v2.5.x it is SKLMConfig.properties
For details, see link: http://www-01.ibm.com/support/docview.wss?uid=swg21960261
You should verify applying this configuration change does not cause any compatibility issues. Not disabling the DHE/DH cipher 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 DHE/DH cipher and take appropriate mitigation and remediation actions.
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References
Acknowledgement
The vulnerability was reported to IBM by The WeakDH team at https://weakdh.org
Change History
12 June 2015: Original version 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:
16 June 2018
UID
swg21960935