84-10-15 Securing Tandem Systems

Tandem computers are employed extensively in heavy volume, OnLine Transaction Processing environments. Tandem systems can be found in 24 of the top 25 US banks; 32 of the top 50 European banks; 250 brokerage and security firms; 60 major insurance companies; and in 40of the world s busiest stock and commodities exchanges. Tandem computers run 75% of all automated teller machine transactions, 66% of all worldwide credit card transactions, and 50% of all public E-mail systems. Despite this large presence in computing environments worldwide, Tandem computers are as yet enigmatic to information security practitioners and information systems auditors. This is primarily because Tandem systems are designed with fault tolerance, low maintenance, and low overhead in mind. In many large financial institutions, only two employees provide Tandem system administration and management (i.e., perform operating system upgrades, capacity planning and tuning, and other related maintenance tasks). Compare this with the number of people generally required to support a large mainframe and it is obvious why the Tandem system is often forgotten until something specific is required of it. Tandem Computers, Inc., which developed its first fault tolerant computer in 1976, is also partially responsible for the lack of security awareness on its systems. Safeguard, the Tandem's security application, is the only security application used with the system. It was not until the company's recent D30 release of the NonStop Kernel—Tandem s operating system—and Safeguard, that Tandem pursued certification of its security environment with the National Computer Security Center (NCSC). Although Tandem's security environment does not provide the controls and granularity of more established and refined security packages, such as CA-ACF2 and RACF, it is possible to secure a Tandem system. This article addresses the various components of Tandem security, focusing on basic NonStop Guardian security, Safeguard security, and the interaction between the two. In addition, the chapter provides suggestions for minimizing risk and improving administration in a Tandem system.