Security Bulletin: A vulnerability in Diffie-Hellman ciphers affects IBM Security Network Intrusion Prevention System (CVE-2015-4000)

Summary

The Logjam Attack on TLS connections using the Diffie-Hellman (DH) key exchange protocol affects IBM Security Network Intrusion Prevention System.

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

Products: GX3002, GX4002, GX4004, GX4004-v2, GX5008, GX5008-v2, GX5108, GX5108-v2, GX5208, GX5208-v2, GX6116, GX7412, GX7412-10, GX7412-05, GX7800, GV200, GV1000

Firmware versions 4.6.2, 4.6.1, 4.6, 4.5, 4.4, and 4.3

Remediation/Fixes

Product

| VRMF| Remediation/First Fix
—|—|—
IBM Security Network Intrusion Prevention System | Firmware version 4.6.2| 4.6.2.0-ISS-ProvG-AllModels-System-FP0009
IBM Security Network Intrusion Prevention System | Firmware version 4.6.1| 4.6.1.0-ISS-ProvG-AllModels-System-FP0013
IBM Security Network Intrusion Prevention System | Firmware version 4.6| 4.6.0.0-ISS-ProvG-AllModels-System-FP0011
IBM Security Network Intrusion Prevention System | Firmware version 4.5| 4.5.0.0-ISS-ProvG-AllModels-System-FP0013
IBM Security Network Intrusion Prevention System | Firmware version 4.4| 4.4.0.0-ISS-ProvG-AllModels-System-FP0013
IBM Security Network Intrusion Prevention System | Firmware version 4.3| 4.3.0.0-ISS-ProvG-AllModels-System-FP0011
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.

Workarounds and Mitigations

As the length of the server key size are increased, the amount of CPU required for full TLS/SSL handshake can significantly increase. Please carefully test and assess the impact to your CPU requirements to ensure sufficient CPU resources, otherwise the system availability may be impacted.
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.