IBM Security Z Security

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  • 1.  zSecure Trusted Report Questions

    Posted Fri September 13, 2024 09:05 AM

    A couple of questions I looked in the document but didn't find clear answers:

    • Does IBM have a definition to what the zSecure Trusted Report is?
    • Is there a table or the like as to what is "Trusted".
    • Is there a way to add/remove things from the trusted report.
      • Particularly backups.  Maybe *.BKUP on the end of a DSN that is considered "Trusted".  The backup contains the same data.

    Thank you,

    Brent Brimacomb

    Wells Fargo



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    Brent Brimacomb
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  • 2.  RE: zSecure Trusted Report Questions

    Posted Fri September 13, 2024 12:36 PM

    Hi Brent, 

    - Does IBM have a definition to what the zSecure Trusted Report is?

    Roughly translated a trusted report shows an overview of users that have one or multiple (indicated by # of reasons) or access path(s) that allows them to update resources that are part of the Trusted Computing Base (TCB) and thus can potentially change security settings/configurations or bypass security measures. For example, users that have SPECIAL, OPERATIONS, UID(0), or UPDATE or higher access to an APF-authorized library are considered 'Trusted users' in this context. This terminology should not be mixed up with the TRUSTED attribute of a started task user, although trusted started task users are considered to be a trusted user in a zSecure Trusted Report. But note that the reverse statement that all trusted users are assigned the TRUSTED attribute is not true. 

    The idea is that using the 'Trusted report', you can review whether the reported trust reasons for the users that are reported align with their current job role. Be aware, that it is impossible design a system that does not have any 'trusted users' reported. Your company will employ security administrators, DB admins, auditors, systems programmers, etc. etc. that need certain trusted access to perform their normal work. As a general rule of the thumb, the trusted report should not report any users that are not involved in z/OS system management in one way or another. And from the remaining trusted users, you can review whether their reported trust reasons correspond with their  job role. If not, the trust reasons that do not align with their job role should be  removed.

    - Is there a table or the like as to what is "Trusted".

    To my knowledge there's no table that documents which privileges and access level to sensitive resources are considered to be "Trusted" access.  The audit concern description and the details in the trusted report can be used to review/diagnose why a certain access is reported as a trust reason and what is the actual source of this access, e.g. possession of a privilege, an UPDATE or higher access to a sensitive resource the user has through a permit, a group connection, or general access (by means of WARNING mode, UACC, ID(*), or global access table).

    - Is there a way to add/remove things from the trusted report.

    Remove: Yes, in principle that is possible. You can add an EXCLUDE SENSITIVIY=(list of sensitivity types that you want to exclude from the report) statement. Or for example when you add a statement like:

    EXCLUDE SENSITIVITY=:prmlib or SENSITIVITY=:loadlb

    The trusted report will skip reporting all sensitivities that show the strings 'prmlib' and 'loadlb' in the sensitivity column. 

    Add: No. I cannot think of a way to add site defined sensitivity types to the zSecure trusted analysis. 

    I hope you find this information useful. 



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    Tom Zeehandelaar
    z/OS Security Enablement Specialist - zSecure developer
    IBM
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  • 3.  RE: zSecure Trusted Report Questions

    Posted Sat September 14, 2024 10:10 AM

    Hi Brent

    Here is an older discussion about TRUSTED.  You can add dsnames and also general resource names to the list of sensitive (critical) resources using the SIMULATE command.  SIMULATE SENSITIVE is meant (only) for data sets, whereas the newer SIMULATE CLASS=xxxx allows specification of data set and resource names.  You must specify a senstype value and a priority for the names to show up in the trusted reports.  See here.



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    Rob van Hoboken
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  • 4.  RE: zSecure Trusted Report Questions

    Posted Mon September 16, 2024 06:01 AM
    Edited by Hans Schoone Mon September 16, 2024 06:17 AM

    Hi Brent,

    >Does IBM have a definition to what the zSecure Trusted Report is?

    Yes, see NEWLIST TYPE=TRUSTED https://www.ibm.com/docs/en/szs/3.1.0?topic=fields-trusted-users-that-can-bypass-security

    In summary, any user who has a privilege or permit at the "risk" access level to a sensitive resource is considered "Trusted".

    >Is there a table or the like as to what is "Trusted".

    The sensitivity types are documented in the CARLa NEWLIST book appendix "Predefined sensitivity types"  https://www.ibm.com/docs/en/szs/3.1.0?topic=fields-predefined-sensitivity-types

    >Is there a way to add/remove things from the trusted report. 

    Yes, for adding the definition of a sensitivity see DEFSENS https://www.ibm.com/docs/en/szs/3.1.0?topic=language-defsens

    For assigning a sensitivity to a resource, see the links Rob provided and SIMULATE https://www.ibm.com/docs/en/szs/3.1.0?topic=language-simulate

    For removing things use the SUPPRESS AUTO_SENSTYPE=senstype command, see SUPPRESS https://www.ibm.com/docs/en/szs/3.1.0?topic=suppress-command-options The doc should have mentioned TRUSTED here as well. As Tom pointed out you can also use an EXCLUDE command to remove report lines from the report, but the SUPPRESS is more efficient.

    > Maybe *.BKUP on the end of a DSN that is considered "Trusted".  The backup contains the same data.

    The intent is that if a data set is read-sensitive backups created through HSM would automatically be considered sensitive as well. But that is still on our to-do list. Adding an Idea in AHa! would raise the priority. For write-sensitive data sets, it would make only marginal sense to declare the backup sensitive (for the case an attacker could force a restore from the backup). If you have applications creating their own backups while adding a qualifier .BKUP at the end, I think another idea in Aha! describing how that works would be warranted, so that we can design an appropriate addition to CARLa for that.



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    Hans Schoone
    Chief Architect zSecure
    IBM - zSecure architect
    Delft
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  • 5.  RE: zSecure Trusted Report Questions

    Posted Fri September 20, 2024 09:35 AM

    Thank you to everyone who replied.  You've given me a lot to think about and digest.

    Very much appreciated!

    Brent Brimacomb

    Wells Fargo



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    Brent Brimacomb
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