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ibmIBM071B3ECF88492CB6DA63393D64D3FB74AB0EB97331D3FB675F3ED64F4D1398E2
HistorySep 08, 2022 - 12:09 a.m.

Security Bulletin: Vulnerability with Diffie-Hellman ciphers may affect IBM WebSphere Application Server (CVE-2015-4000)

2022-09-0800:09:56
www.ibm.com
460

3.7 Low

CVSS3

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

LOW

Availability Impact

NONE

CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

4.3 Medium

CVSS2

Access Vector

NETWORK

Access Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

PARTIAL

Availability Impact

NONE

AV:N/AC:M/Au:N/C:N/I:P/A:N

0.975 High

EPSS

Percentile

100.0%

Summary

The LogJam Attack on Diffie-Hellman ciphers (CVE-2015-4000) may affect some configurations of IBM WebSphere Application Server Full Profile, IBM WebSphere Application Server Liberty Profile, and IBM WebSphere Application Server Hypervisor Edition. The IBM HTTP Server used by WebSphere Application Server is not affected.

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 WebSphere Application Server Versions may be affected:

  • Version 8.5 and 8.5.5 Full Profile and Liberty Profile
  • Version 8
  • Version 7
  • Version 6.1

Remediation/Fixes

For IBM WebSphere Application Server and IBM WebSphere Application Server Hypervisor Edition****:

You should apply the correct Interim Fix as noted below for your version of the IBM SDK Java Technology Edition. You will also need to update your java.security file to add

jdk.tls.disabledAlgorithms=SSLv3, RC4, DH keySize < 768

Adding this line to the java.security file will disable features exploited by Poodle, RC4 (Bar Mitzvah), and logjam vulnerabilities.
The IBM Java SDK already has SSLv3 disabled by default and the WebSphere Application Server default configuration does not have any RC4 Ciphers. As such adding the jdk.tls.disabledAlgorithims= for SSLv3 and RC4 is redundant but is consistent with what is required for a stand alone JDK. The java.security file must be updated on the client side with the DH keySize so that is it not vulnerable to the logjam attack. The DH Keysize<768 means that the client will only accept DH keys greater than or equal to 768.

APAR IV73934 - includes the fix for CVE-2015-4000 for IBM SDK, Java Technology Edition, Versions 6, 7 and 8
APAR IV73962 - includes the fix for CVE-2015-4000 for IBM SDK, Java 2 Technology Edition Version 5

Download and apply the interim fix APARs below, for your appropriate release

For V8.5.0.0 through 8.5.5.6 Liberty Profile:

Upgrade to WebSphere Application Server Liberty Profile Fix Pack 8.5.5.1 or later then apply one of the interim fixes below:

  • Apply Interim Fix PI42781: Will upgrade you to IBM SDK, Java Technology Edition, Version 6R1 Service Refresh 8 (required) +IX90162+IV73188+IV73636+IV73934

  • Apply Interim Fix PI42775: Will upgrade you to IBM SDK, Java Technology Edition, Version 7 Service Refresh 9 (optional) +IX90162+IV73188+IV73636+IV73934

  • Apply Interim Fix PI42774: Will upgrade you to IBM SDK, Java Technology Edition, Version 7R1 Service Refresh 3 (optional) +IX90162+IV73188+IV73636+IV73934

  • Apply Interim Fix PI42733: Will upgrade you to IBM SDK, Java Technology Edition, Version 8 Service Refresh 1 (optional) +IX90162+IV73188+IV73636+IV73934
    --OR–

  • Apply IBM Java SDK shipped with WebSphere Application Server Fix pack 7 (8.5.5.7) or later.

For V8.5.0.0 through 8.5.5.6 Full Profile:

Upgrade to WebSphere Application Server Full Profile Fix Pack 8.5.5.1 or later then apply one of the interim fixes below:

  • Apply Interim Fix PI42776: Will upgrade you to IBM SDK, Java Technology Edition, Version 6R1 Service Refresh 8 Fix Pack 4 (required) +IX90162 +IV73188 +IV73636 +IV73934

  • Apply Interim Fix PI42775: Will upgrade you to IBM SDK, Java Technology Edition, Version 7 Service Refresh 9 (optional) +IX90162+IV73188+IV73636+IV73934

  • Apply Interim Fix PI42774: Will upgrade you to IBM SDK, Java Technology Edition, Version 7R1 Service Refresh 3 (optional) +IX90162+IV73188+IV73636+IV73934
    --OR–

  • Apply IBM Java SDK shipped with the WebSphere Application Server Fix pack 7 (8.5.5.7) or later.

For V8.0.0.0 through 8.0.0.10:

Upgrade to WebSphere Application Server Fix Pack 8.0.0.7 or later then apply the interim fix below:

  • Apply Interim Fix PI42777: Will upgrade you to IBM SDK, Java Technology Edition, Version 6R1 Service Refresh 8 Fix Pack 4 +IX90162+IV73188+IV73934
    --OR–

  • Apply IBM Java SDK shipped with WebSphere Application Server Fix pack 11 (8.0.0.11) or later.

For V7.0.0.0 through 7.0.0.37:

Upgrade to WebSphere Application Server Fix Pack 7.0.0.31 or later then apply the interim fix below:

  • Apply Interim Fix PI42778: Will upgrade you to IBM SDK, Java Technology Edition, Version 6 Service Refresh 16 Fix Pack 4 +IX90162+IV73934
    --OR–

  • Apply IBM Java SDK shipped with WebSphere Application Server Fix pack 39 (7.0.0.39) or later.

For V6.1.0.0 through 6.1.0.47:

Upgrade to WebSphere Application Server Fix Pack 6.1.0.47

  • Then apply Interim Fix PI42779: Will upgrade you to IBM SDK, Java 2 Technology Edition, Version 5.0 Service Refresh 16 Fix Pack 11 (which includes IV73962)

NOTE: 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.

After you have applied the correct Interim fix for your version of the IBM SDK Java Technology Edition. You will also need to update your java.security file to add

jdk.tls.disabledAlgorithms=SSLv3, RC4, DH keySize &lt; 768

Adding this line to the java.security file will disable features exploited by Poodle, RC4 (Bar Mitzvah), and logjam vulnerabilities.
The IBM Java SDK already has SSLv3 disabled by default and the WebSphere Application Server default configuration does not have any RC4 Ciphers. As such adding the jdk.tls.disabledAlgorithims= for SSLv3 and RC4 is redundant but is consistent with what is required for a stand alone JDK. The java.security file must be updated on the client side with the DH keySize so that is it not vulnerable to the logjam attack. The DH Keysize<768 means that the client will only accept DH keys greater than or equal to 768.

For IBM WebSphere Application Server for i5/OS operating systems:

The IBM Developer Kit for Java is prerequisite software for WebSphere Application Server for IBM i. Please refer to Java on IBM i for updates on when these fixes will be available.

Workarounds and Mitigations

The Logjam attack which affects TLS connections using the Diffie-Hellman (DH) key exchange protocol may affect some configurations in WebSphere Application Server.
WebSphere Application Server has DH and DHE ciphers included in the “STRONG” or “HIGH”, “MEDIUM” and “LOW” cipher lists. They also could be present if you have a “CUSTOM” list of ciphers. You will need to remove any of the ciphers that begin with SSL_* or TLS_* that also have DH or DHE in the Name from your WebSphere Application Server SSL configuration. This does NOT include ciphers that have ECDH or ECDHE in the Name, these are elliptic curve Diffie-Hellman ciphers and they are not affected.

For Full profile:

  • You can view the administrative console page to change the settings, click Security > SSL certificate and key management. Under Configuration settings, click** Manage endpoint security configurations > {Inbound | Outbound} >****ssl_configuration. Under Related items, clickSSL configurations > . Click on {SSL_configuration_name }. UnderAdditional Properties**, clickQuality of protection (QoP) settings.

OR

For Liberty profile:

Outbound connections from WebSphere Application Server are impacted but inbound connections are not.

You should verify applying this configuration change does not cause any compatibility issues. Not disabling the DH or DHE stream ciphers will expose yourself to the Logjam 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.

3.7 Low

CVSS3

Attack Vector

NETWORK

Attack Complexity

HIGH

Privileges Required

NONE

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

LOW

Availability Impact

NONE

CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

4.3 Medium

CVSS2

Access Vector

NETWORK

Access Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

PARTIAL

Availability Impact

NONE

AV:N/AC:M/Au:N/C:N/I:P/A:N

0.975 High

EPSS

Percentile

100.0%

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