DB2: Internal Subsystem Security vs. External Security Manager (ESM)?

With the ever increasing requirement for regulatory compliance and the clear and present danger associated with cybersecurity attacks, isn’t now the best time to safeguard your organizations most important asset, namely business data?  Various industry analyst quotes state that ~80%+ of Mainframe data resides in databases and associated data sources and ~80%+ of global corporate data originates or resides on IBM Mainframes.  Depending on your viewpoint, rightly or wrongly DB2 is the most pervasive of database subsystems, offering two mechanisms for security, either internal subsystem or External Security Manager (ESM) based via ACF2, RACF or Top Secret.  When DB2 was first released in 1983, Mainframe security was in its infancy and perhaps even an afterthought, and so implementing internal DB2 security might have been the typical approach for many years.  Some several decades later, asking that age old rhetorical question; what is the best security solution for my mission critical and priceless data?  I’m not sure it is a rhetorical question, the answer is patently obvious, external security!

RACF and DB2 security integration was introduced in 1997 with OS/390 2.4 and DB2 Version 6 and so a ~14 year period where DB2 internal security was the only option!  Personally, ~20 years ago I was involved with an internal DB2 to RACF security migration project, part of a larger Operating System, DB2 and indeed CICS upgrade.  Basically the DB2 DBA team stated “we would have never implemented internal DB2 security if the RACF option was available; can you migrate to RACF for us”?  The simple reality being that Security Management is not a core DBA skill and such a process is ideally delivered by a Subject Matter Expert (SME).  Of course, DB2 was somewhat straightforward ~20 years ago, as were its security features, but in the last ~20 years, DB2 has become more complex and enterprise wide, while I’m often surprised by the number of organizations I encounter, both small and large, still deploying internal DB2 security…

Recognizing a ~20 year longevity period of RACF security support for DB2, maybe even the most conservative of organizations might concede that the technology is proven and works?  From a business viewpoint, such a migration from DB2 internal to an External Security Manager (ESM) is the proverbial “no brainer”, because:

  • Subject Matter Expert (SME): Clearly all IBM Mainframe organizations now have dedicated security professionals who are ideally placed to implement enterprise wide security policies. A DB2 DBA is a highly skilled SME in their own discipline, most likely welcoming the migration of security from DB2 to ACF2, RACF or Top Secret.
  • Compliance: A plethora of industry regulations, including but not limited to GLB, SOX, PCI-DSS, et al, dictate that a hybrid of technical skills and business policy knowledge is required. This has generated a requirement for the executive level CISO role and associated security certifications (E.g. CISA, CISM, CISSP) for SME resources.
  • Auditability: From a board level CxO viewpoint, which technical resource would you want responsible for your security policy, the CISO/CIO and their security engineers or a DB2 DBA?
  • Hacking-Penetration Testing: Rightly or wrongly, rightly in my opinion, Penetration (Pen) Testing is a methodology to try and hack a system in order to highlight security vulnerabilities, supplementing the traditional periodic audit processes. Once again, high levels of security expertise are required for such activities.

From a technical viewpoint, what is the complexity of performing a DB2 internal to RACF external security migration?

From a DB2 viewpoint, internal security rules are stored in DB2 catalog tables with the SYSIBM.SYSxxxAUTH naming convention.  Therefore these data repositories can be processed with a simplistic DB2 to RACF security migration tool (RACFDB2).  As per any migration activity, Garbage In, Garbage Out (GIGO) applies, and this golden rule dictates the requirement for a collaborative team effort to execute a DB2 to RACF security migration process.  Of course, the most important resources will be the DB2 DBA(s) responsible for maintaining DB2 security and a RACF SME.  Between them, these 2 resources have all of the skills required to perform this migration process, if not the experience.

From a documentation viewpoint, there are several resources that can be referenced to simplify this process:

The purpose of this blog post is a “call to action”, for those sites still deploying DB2 internal security, to migrate to their External Security Manager (ESM), whether ACF2, RACF or Top Secret.  There are also options for the migration of internal DB2 security to CA ACF2 and Top Secret respectively.

As previously stated, the DB2 DBA will be ideally placed to review the existing internal DB2 security environment, performing any clean-up and rationalization before the actual migration process.  The initial pass of the migration process will inevitably produce a one:one (1:1) mapping of rules, generating numerous security definitions extraneous to requirements.  This is where the ACF2, RACF or Top Secret SME can collaborate with their DB2 DBA, applying grouping, masking and generic filters to vastly reduce and simplify the number of security definitions required.  As with any migration, perform on the lowest level non-Production environment first, apply the lessons learned, and use common sense, issuing warning messages for inadvertent security policy errors, as opposed to denying security access for Production migrations!  Therefore allowing for the smooth transition from DB2 internal to ESM based security.

In my opinion, each and every IBM Mainframe organization has the ability to initiate this DB2 internal to external ACF2, RACF or Top Secret migration project.  Leveraging from 3rd party organizations also makes sense and in no particular order, other than alphabetical, I would suggest IBM Global Services, millennia, RSM Partners or Vanguard.

In conclusion, the IBM System z External Security Manager (ESM), whether ACF2, RACF or Top Secret is an ever-evolving solution with highly advanced security functionality and the de facto central repository for IBM Mainframe security policy management.  From a Security Information & Event Management (SIEM) integration viewpoint, any IBM Mainframe security policy violations will be reported upon in near real-time, while being managed by IBM Mainframe security experts.  Without doubt, if DB2 was implemented before 1997, internal security would have applied, but there has been a ~20 year period where migration to the ACF2, RACF or Top Secret ESM could have happened.  If such a migration activity applies to your organization, I would hope it’s a high priority item, given the potential security risk and priceless value of your business data!