In the ongoing process of securing your system, you may choose to address the default setting of the QCRTAUT system value.
Before I get into the considerations you need to make before changing this value, let's discuss the purpose of the QCRTAUT system value.
What Is QCRTAUT?
QCRTAUT (Create authority) provides the *PUBLIC authority setting when most i5/OS objects are created. The next time you create a new file or data area, prompt (Press F4 on) the command and look for the Authority (AUT) parameter. For most Create commands, the AUT parameter defaults to the value *LIBCRTAUT. What is *LIBCRTAUT? The library that the object is being created into has an attribute called Create Authority. *LIBCRTAUT means to set the *PUBLIC authority of the object being created to the value of the library's Create authority attribute. What is the library's Create authority attribute? The default is *SYSVAL, which means that it uses the value of the QCRTAUT system value. So when an object is created, its *PUBLIC authority defaults to *LIBCRTAUT, which says to look at the library's Create authority, which defaults to look at the QCRTAUT system value. Because the value of QCRTAUT is shipped by IBM as *CHANGE, most objects on the system are created with *PUBLIC authority *CHANGE.
Considerations Before Changing QCRTAUT
Now let's look at the considerations to make before changing QCRTAUT. First, it should go without saying that QCRTAUT should never be changed to *ALL. However, it is appropriate to consider changing it to *USE or *EXCLUDE. When I guide clients through the process of changing QCRTAUT, we start by getting a list of the libraries on the system and downloading it to a spreadsheet. You can use SkyView Policy Minder to do this by creating a *LIBAUT template that includes all libraries. (Don't bother creating an object template.) Run a compliance check on this template, and then run the Output Compliance (OUTCPL) command from the SKYVIEWPMP library, specifying STATUS(*ALL). This will create a file in the /SkyView/Policy Minder directory that you can drag onto your desktop and open with Excel.
Once you have the spreadsheet, separate the libraries into four categories: IBM/IBM licensed product libraries, vendor product libraries, application libraries, and user/developer libraries. Then, determine whether the libraries' Create authority attribute should either remain at *SYSVAL or be overridden with a specific value.
You can typically leave the IBM libraries with their current settings. (You will see some with their Create authority attribute set to *SYSVAL and some overridden with a specific value such as *CHANGE.)
For the vendor libraries, we consider whether objects (programs, commands, files, etc.) are being created into the libraries or are just being utilized. If it's the latter, we leave those library settings alone as well. If objects are being created into the libraries, you have to consider whether the vendor product will continue to work correctly if the *PUBLIC authority of the newly created objects is set to *USE or *EXCLUDE. If it won't run correctly, you can consider changing those libraries' Create authority value to *CHANGE.
For the application libraries, you must consider whether the application's security scheme will support newly created objects with a *PUBLIC authority of *USE or *EXCLUDE. If it won't, you'll be forced into leaving those objects created with *PUBLIC *CHANGE. To continue to have the objects created with *PUBLIC *CHANGE, set the Create authority attribute of those libraries to *CHANGE.
Personal or user libraries can typically be left at *SYSVAL because it is usually the individual user accessing the objects in his or her library, and the *PUBLIC authority setting won't matter.
A little-known fact is that you can specify an authorization list for a library's Create authority value. I have used this feature when reworking an application's security scheme and securing the application's files with an authorization list. It works especially well when the application files are in a library that's separate from the application programs. I specify the authorization list name for the library's Create authority value, and from then on, all objects created into the library will be secured with that authorization list.
How Policy Minder Helps
When creating a Library authority (*LIBAUT) template, you can specify the appropriate value for the library's Create authority attribute. Then you can run regular compliance checks to ensure that this library attribute remains set correctly. In addition, you can run compliance checks on the System value (*SYSVAL) category to ensure that the QCRTAUT system value remains set to the appropriate value.
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