Is the IBM i secure or irrelevant? IBM i object security vs. Win and UNIX file security

1 04 2010

A critical security consideration for any operating system is how it secures ‘files’. Although the contexts may deffer, both Windows and UNIX encapsulate all types of information in fies of various types. IBM i, on the other hand, encapsulates information in various types of objects. Different objects require different types of access.

If I know the name and path of a file under Windows or UNIX, I know its location and can access it by knowing how to read and navigate the file structures. Under IBM i, objects in the native, library file system are located and constructed via sets of pointers. Knowing how to read and navigate the file structures only leads you to bits and pieces of an object’s definition. As a result, hacking an IBM i system requires an order of magnitude greater knowledge and sophistication than hacking either Windows or UNIX.

UNIX secures files at owner, group and public levels for read, write and execute access. Older versions of Windows only secured files via read-only, hidden and archive permissions attributes. Newer versions of Windows and many UNIX systems also provide Access Control Lists (ACLs) to secure ‘objects’ against access via user’s without proper permissions or authority. From it’s earliest days, starting with System/38, the IBM i series provided true object access control at multiple levels of an object’s definition. At the higher object definition level, the system provides Operational, Management, Existence, Alter and Reference control. For objects containing data, the system additionally provides Read, Add, Update, Delete and Execute control. What is more, file definitions can extend access controls to the field level. For the UNIX and Windows like file systems which are part of the Integrated File System, native object access controls are used to emulate UNIX access controls.

At a higher level, authority lists provide the ability to control object access for multiple objects using a single, easy to manage object. And, IBM i supports ACLs in limited environments.

Therefore, IBM i provides very mature and sophisticated access control mechanisms with a great deal of granularity. This is part of the reason IBM i systms are compromized far less often than are Windows and UNIX systems.