Security Bulletin
Summary
The Logjam Attack on TLS connections using the Diffie-Hellman (DH) key exchange protocol affects IBM Tivoli Netcool System Service Monitors/Application Service Monitors.
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
SSM 4.0.0 FP1 - FP14 and Interim Fix 14-01 – Interim Fix 14-06
SSM 4.0.1 FP1 – FP2 Interim Fix 02
Remediation/Fixes
None
Workarounds and Mitigations
Modify the INIVAR FileTransferSSLCipherSuite in init.cfg. This is currently:
FileTransferSSLCipherSuite=AES:3DES:DES:!EXP
Disable the DHE and EDH Ciphers by changing it to the following and restarting SSM:
FileTransferSSLCipherSuite=AES:3DES:DES:!EXP:!DHE:!EDH
Note that as this is a new INIVAR this mitigation requires applying either of the following fixes first:
SSM 4.0.1.2 Interim Fix 2 - http://www.ibm.com/support/docview.wss?uid=isg400002115
SSM 4.0.0.14 Interim Fix 6 - http://www.ibm.com/support/docview.wss?uid=isg400002120
You should verify applying this configuration change does not cause any compatibility issues. If you change the default setting after applying the fix, you 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 Diffie-Hellman key-exchange protocol used in TLS and take appropriate mitigation and remediation actions.
Get Notified about Future Security Bulletins
References
Acknowledgement
Reported to IBM by The WeakDH team at https://weakdh.org
Change History
5 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.
Was this topic helpful?
Document Information
Modified date:
17 June 2018
UID
swg21959128