Secure Socket Layer version 3 (SSLv3) is largely obsolete, but some software does occasionally fall back to this version of SSL protocol. The bad news is that SSLv3 contains a vulnerability that exposes systems to a potential attack. The vulnerability is nicknamed POODLE, which stands for Padding Oracle On Downgraded Legacy Encryption.
The vulnerability does affect IBM WebSphere MQ because SSLv3 is enabled by default in MQ.
IBM describes the vulnerability like this: IBM WebSphere MQ could allow a remote attacker to obtain sensitive information, caused by a design error when using the SSLv3 protocol. A remote user with the ability to conduct a man-in-the-middle attack could exploit this vulnerability via a POODLE (Padding Oracle On Downgraded Legacy Encryption) attack to decrypt SSL sessions and access the plaintext of encrypted connections.”
The vulnerability affects all versions and releases of IBM WebSphere MQ, IBM WebSphere MQ Internet Pass-Thru and IBM Mobile Messaging and M2M Client Pack.
To harden against the vulnerability, users should disable SSLv3 on all WebSphere MQ servers and clients and instead use the TLS protocol. More specifically, WebSphere MQ channels select either SSL or TLS protocol from the channel cipherspec. The following cipherspecs are associated with the SSLv3 protocol and channels that use these should be changed to use a TLS cipherspec:
AES_SHA_US
RC4_SHA_US
RC4_MD5_US
TRIPLE_DES_SHA_US
DES_SHA_EXPORT1024
RC4_56_SHA_EXPORT1024
RC4_MD5_EXPORT
RC2_MD5_EXPORT
DES_SHA_EXPORT
NULL_SHA
NULL_MD5
FIPS_WITH_DES_CBC_SHA
FIPS_WITH_3DES_EDE_CBC_SHA
On UNIX, Linux, Windows and z/OS platforms, FIPS 140-2 compliance mode enforces the use of TLS protocol. A summary of MQ cipherspecs, protocols and FIPS compliance status can be found here.
On the IBM i platform, use of the SSLv3 protocol can be disabled at a system level by altering the QSSLPCL system value. Use Change System Value (CHGSYSVAL) to modify the QSSLPCL value, changing the default value of *OPSYS to a list that excludes *SSLV3. For example: *TLSV1.2, *TLSV1.1, TLSV1.
TxMQ is an IBM Premier Business Partner and “MQ” is part of our name. For additional information about this vulnerability and all WebSphere-related matters, contact president Chuck Fried: 716-636-0070 x222, chuck@TxMQ.com.
TxMQ recently introduced its MQ Capacity Planner – a new solution developed for performance-metrics analysis of enterprise-wide WebSphere MQ (now IBM MQ) infrastructure. TxMQ’s innovative technology enables MQ administrators to measure usage and capacity of an entire MQ infrastructure with one comprehensive tool.
(Photo from J Jongsma)
