Security Bulletin: Vulnerability in RC4 stream cipher affects IBM FlashSystem 900 (CVE-2015-2808)

Summary

The RC4 “Bar Mitzvah” Attack for SSL/TLS affects the IBM FlashSystem 900.

Vulnerability Details

CVEID: CVE-2015-2808 DESCRIPTION: The RC4 algorithm, as used in the TLS protocol and SSL protocol, could allow a remote attacker to obtain sensitive information. An attacker could exploit this vulnerability to remotely expose account credentials without requiring an active man-in-the-middle session. Successful exploitation could allow an attacker to retrieve credit card data or other sensitive information. This vulnerability is commonly referred to as “Bar Mitzvah Attack”.
CVSS Base Score: 5
CVSS Temporal Score: See https://exchange.xforce.ibmcloud.com/vulnerabilities/101851 for the current score
CVSS Environmental Score*: Undefined
CVSS Vector: (AV:N/AC:L/Au:N/C:P/I:N/A:N)

Affected Products and Versions

IBM FlashSystem 900 including machine type and models (MTMs) for all available code levels. MTMs affected include 9843-AE2 and 9840-AE2.

Remediation/Fixes

Product

| VRMF | APAR | Remediation/First Fix
—|—|—|—
FlashSystem 900 MTMs:

9840-AE2

9843-AE2

| The VRMF of the present code level is 1.2.0.11, and while RC4 is enabled by default, it supports the workaround described below. A code fix which disables RC4 as a default is being developed, but is not presently available. | None |

This issue is fixed in 1.2.1.8 firmware.

The only way to address this vulnerability in older firmware is by use of the workaround described in the following section.

IBM recommends that you review your entire environment to identify other areas where you have enabled the RC4 stream cipher and take appropriate mitigation and remediation actions.

_IBM recommends upgrading to a fixed, supported version/release/platform of the product as soon as it is available. _

This vulnerability is first fixed in 1.2.1.8.

Workarounds and Mitigations

The default security_level setting of the SSL protocol is 1, and RC4 is enabled when the security_level is at this default value of 1. But the user can increase the security level of the SSL protocol from 1 to either 2 or 3 by issuing the following command from the CLI, replacing words in italics with actual values:

svctask chsecurity –sslprotocol security_level

To view the security level, issue svcinfo lssecurity

Here is what the security level settings mean:
· 1 disallows SSL 3.0
· 2 allows TLS 1.2 only
· 3 additionally disallows TLS 1.2 cipher suites that are not exclusive to 1.2

At whatever security level you choose to operate, you should verify applying this configuration change does not cause any compatibility issues. Not disabling the RC4 stream 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 RC4 stream cipher and take any necessary precautions.