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Security Bulletin: Vulnerabilities in GSKit affect Security Access Manager for DataPower (CVE-2015-0159, CVE-2015-0138)

Security Bulletin


GSKit is an IBM component that is used by Security Access Manager components on DataPower. The GSKit that is shipped with Security Access Manager contains several security vulnerabilities including the “FREAK: Factoring Attack on RSA-EXPORT keys" TLS/SSL client and server vulnerability. The Security Access Manager components on DataPower have addressed the applicable CVEs.

Both the Access Manager Reverse Proxy introduced in DataPower version 7.1 and the Access Manager Client are affected.

Vulnerability Details

CVEID: CVE-2015-0138

A vulnerability in various IBM SSL/TLS implementations could allow a remote attacker to downgrade the security of certain SSL/TLS connections. An IBM SSL/TLS client implementation could accept the use of an RSA temporary key in a non-export RSA key exchange ciphersuite. This could allow a remote attacker using man-in-the-middle techniques to facilitate brute-force decryption of TLS/SSL traffic between vulnerable clients and servers.

This vulnerability is also known as the FREAK attack.

CVSS Base Score: 4.3
CVSS Temporal Score: See for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (AV:N/AC:M/Au:N/C:N/I:P/A:N)

CVEID: CVE-2015-0159

DESCRIPTION: An unspecified error in GSKit usage of OpenSSL crypto function related to the production of incorrect results on some platforms by Bignum squaring (BN_sqr) has an unknown attack vector and impact in some ECC operations.

CVSS Base Score: 2.6
CVSS Temporal Score: See for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (AV:N/AC:H/Au:N/C:N/I:P/A:N)

Affected Products and Versions

IBM DataPower Gateway appliances all versions through,,,


Fix is available in versions,,, Refer to APAR IT07604.

The remediation for CVE-2015-0138 also remediates CVE-2014-8730 "TLS Padding Vulnerability" (also known as "POODLE 2"). Communication errors can occur if both ends of the TLS connection do not observe the same strict CBC padding requirements required to remediate POODLE 2. See the Workarounds and Mitigations section below for more detail.

For DataPower customers using versions 5.x and older versions, IBM recommends upgrading to a fixed, supported version/release/platform of the product.

Workarounds and Mitigations

You should verify applying this fix does not cause any compatibility issues.

The remediation for CVE-2014-8730 enforces strict CBC padding checks by the client. If the server does not implement strict CBC padding checks, the client will reject the TLS data packet and report an error.

IBM STRONGLY recommends that all servers in the Access Manager environment be upgraded to a version of GSKit (or third-party SSL stack) that remediates the TLS Padding Vulnerability (CVE-2014-8730). If clients and servers are mis-matched with respect to this remediation, intermittent communication errors can occur when the client expects strict padding and the server does not implement it.

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*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.

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Document Information

Modified date:
15 June 2018