IBM SECURITY ADVISORY
First Issued: Mon Apr 27 15:27:04 CDT 2015
The most recent version of this document is available here:
http://aix.software.ibm.com/aix/efixes/security/rc4_advisory.asc
https://aix.software.ibm.com/aix/efixes/security/rc4_advisory.asc
ftp://aix.software.ibm.com/aix/efixes/security/rc4_advisory.asc
Security Bulletin: Vulnerability in RC4 stream cipher
affects AIX (CVE-2015-2808)
===============================================================================
SUMMARY:
The RC4 .Bar Mitzvah. Attack for SSL/TLS affects GSKit, IBM SDK for Java,
and IBM SDK for Node.js on AIX.
===============================================================================
VULNERABILITY DETAILS:
CVEID: CVE-2015-2808
http://cve.mitre.org/cgi-bin/cvename.cgi?name=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:
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:
AIX 5.3, 6.1, 7.1
VIOS 2.2.x
The following versions of GSKit are vulnerable:
All 7.0.5.xx 8.0.14.xx 8.0.50.xx
The following versions of IBM SDK for Node.js are vulnerable:
IBM SDK for Node.js v1.1.0.13 and previous releases.
The following fileset levels (VRMF) are vulnerable, if the
respective Java version is installed:
For Java5: Less than or equal to 5.0.0.590
For Java6: Less than or equal to 6.0.0.470
For Java7: Less than or equal to 7.0.0.195
For Java7.1: Less than or equal to 7.1.0.75
Note: to find out whether the affected Java filesets are installed
on your systems, refer to the lslpp command found in AIX user's guide.
Example: lslpp -L | grep -i java
REMEDIATION:
IBM SDK for Java (see Workarounds and Mitigations for Java 7.0 and 7.1
releases):
IBM SDK, Java Technology Edition, Version 5.0 Service Refresh 16
Fix Pack 9 and later:
32-bit: https://www-933.ibm.com/support/fixcentral
/swg/selectFixes?parent=ibm~WebSphere&product=ibm/IBM
+SDKs+for+Java+Technology/Java+Standard+Edition+%28Java
+SE%29&release=5.0.0.0&platform=AIX+32-bit,+pSeries&function=all
64-bit: https://www-933.ibm.com/support/fixcentral
/swg/selectFixes?parent=ibm~WebSphere&product=ibm/IBM
+SDKs+for+Java+Technology/Java+Standard+Edition+%28Java
+SE%29&release=5.0.0.0&platform=AIX+64-bit,+pSeries&function=all
IBM SDK, Java Technology Edition, Version 6 Service Refresh 16 Fix
Pack 3 and later:
32-bit: https://www-933.ibm.com/support/fixcentral
/swg/selectFixes?parent=ibm~WebSphere&product=ibm/IBM
+SDKs+for+Java+Technology/Java+Standard+Edition+%28Java
+SE%29&release=6.0.0.0&platform=AIX+32-bit,+pSeries&function=all
64-bit: https://www-933.ibm.com/support/fixcentral
/swg/selectFixes?parent=ibm~WebSphere&product=ibm/IBM
+SDKs+for+Java+Technology/Java+Standard+Edition+%28Java
+SE%29&release=6.0.0.0&platform=AIX+64-bit,+pSeries&function=all
IBM SDK for Node.js:
IBM SDK for Node.js, v1.1.0.14 and later:
http://www.ibm.com/developerworks/web/nodesdk/
GSKit:
No fixes currently available. Please see Workarounds and
Mitigations.
You should verify applying these fixes do not cause any
compatibility issues. The fix disables RC4 stream cipher by default.
If you change this setting 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 RC4
stream cipher and take appropriate mitigation and remediation actions.
WORKAROUNDS AND MITIGATIONS:
For Java 7.0 and 7.1:
1. Disabling RC4. The can be achieved by adding RC4 to the list of
disabled algorithms defined by the jdk.tls.disabledAlgorithms
security property in java.security file.
2. Not explicit enabling the RC4 cipher suite(s).
3. For HttpsURLConnection, set https.cipherSuites system property to
not include RC4 cipher suites.
4. Configure to be in FIPS 140-2, Suite B or SP800-131a transition or
strict compliance
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 appropriate mitigation
and remediation actions.
For GSKit V7 or less:
Consider implementing one of the mitigation methods described below:
1. Disable RC4 by explicit CipherSuite Selection
e.g.
gsk_attribute_set_buffer( gskhandle, GSK_V2_CIPHER_SPECS, , 0);
gsk_attribute_set_buffer( gskhandle, GSK_V3_CIPHER_SPECS, 352F0A,
0);
gsk_attribute_set_buffer( gskhandle, GSK_TLS_CIPHER_SPECS, 352F0A,
0);
2. Enable SSL FIPS Mode
e.g.
gsk_attribute_set_enum( gskhandle, GSK_SSL_FIPS_MODE_PROCESSING,
, GSK_SSL_FIPS_MODE_PROCESSING_ON);
3. Enable GSK_VACCINATE (when available)
e.g.
gsk_attribute_set_enum( gskhandle, GSK_VACCINATE, GSK_TRUE);
For GSKit V8:
Consider implementing one of the mitigation methods described below:
1. Disable RC4 by explicit CipherSuite Selection
e.g.
gsk_attribute_set_buffer( gskhandle, GSK_V2_CIPHER_SPECS, , 0);
gsk_attribute_set_buffer( gskhandle,
GSK_TLS12_TLS11_TLS10_CIPHER_SPECS,
TLS_RSA_WITH_AES_128_GCM_SHA256,
TLS_RSA_WITH_AES_256_GCM_SHA384,
TLS_RSA_WITH_AES_128_CBC_SHA256,
TLS_RSA_WITH_AES_256_CBC_SHA256,
TLS_RSA_WITH_AES_128_CBC_SHA,
TLS_RSA_WITH_AES_256_CBC_SHA,
TLS_RSA_WITH_3DES_EDE_CBC_SHA,
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA,
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA,
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA256,
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA384,
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256,
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384,
TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256,
TLS_ECDHE_ECDSA_WITH_AES_256_GCM_SHA384,
TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256,
TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384, 0);
2. Enable SSL FIPS Mode
e.g.
gsk_attribute_set_enum( gskhandle, GSK_SSL_FIPS_MODE_PROCESSING,
, GSK_SSL_FIPS_MODE_PROCESSING_ON);
3. Enable GSK_VACCINATE (except 8.0.14.xx)
e.g.
gsk_attribute_set_enum( gskhandle, GSK_VACCINATE, GSK_TRUE);
4. Enable SP800-131A Mode
5. Enable Suite B Mode (note: may cause interop problems)
Environment Variables
Warning: Environment variables are generally overridden by API
calls or ignored by SetUID processes and as such this method is
NOT RECOMMENDED and is considered insecure as it can also become
an attack vector.
Additional Notes:
Vulnerable SSL Clients that have TLS V1.0 or SSL V3.0 enabled and
have been using RC4 as a mitigation against BEAST which are now
disabling RC4 SHOULD also consider using
GSK_TLS_CBCPROTECTION_METHOD set to
GSK_TLS_CBCPROTECTION_METHOD_ONEBYTEFRAGMENT as alternative BEAST
mitigation.
===============================================================================
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REFERENCES:
Complete CVSS Guide: http://www.first.org/cvss/cvss-guide.html
On-line Calculator V2:
http://nvd.nist.gov/cvss.cfm?calculator&adv&version=2
ACKNOWLEDGEMENTS:
None.
CHANGE HISTORY:
First Issued: Mon Apr 27 15:27:04 CDT 2015
===============================================================================
*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
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.
