IBM zSecure Suite Security Technical Implementation Guide

If the zSecure application were to allow any user to make changes to software libraries, those changes might be implemented without undergoing the appropriate testing and approvals that are part of a robust change management process. This requirement applies to applications with software libraries that are accessible and configurable, as in the case of interpreted languages. Software libraries also include privileged programs that execute with escalated privileges. Only qualified and authorized individuals must be allowed to obtain access to information system components to initiate changes, including upgrades and modifications.

IBM Security zSecure STC have the ability to use privileged functions and/or have access to sensitive data. Failure to properly restrict access to these zSecure STC data sets could result in violating the integrity of the base product, which could compromise the operating system or sensitive data.

If zSecure were to allow inappropriate reading or updating of user data sets, sensitive information could be disclosed, or changes might result in incorrect results reported by the product. Only qualified and authorized individuals must be allowed to create, read, update, and delete zSecure user data sets.

Started tasks and batch job IDs can be automatically revoked accidentally if not properly protected. When properly protected STCs prevent any attempts to log on with a password, it eliminates the possibility of revocation due to excessive invalid password attempts (denial of service).

Functional access (which is controlled with access to XFACILIT profiles) must not commingle multiple functions under a single resource profile.

Preventing nonprivileged users from executing privileged zSecure functions mitigates the risk that unauthorized individuals or processes may gain unnecessary access to information or privileges. Privileged functions include, for example, running COLLECT jobs, generating audit reports, and adjusting RACF security settings. Nonprivileged users are individuals who do not possess appropriate authorizations. Circumventing intrusion detection and prevention mechanisms or malicious code protection mechanisms are examples of privileged functions that require protection from nonprivileged users.

Users authorized to use the zSecure program CKFCOLL can collect z/OS system information that is not accessible to regular users. Users authorized to use the zSecure program CKGRACF can change certain permitted RACF profile definitions that otherwise would not be allowed. Users authorized to use the zSecure program CKRCARLX can fake SMF records. Allowing inappropriate users to use the CKFCOLL, CKGRACF, and CKRCARLX programs could result in disclosure of z/OS installation and configuration information or inappropriate RACF profile or SMF record changes. Satisfies: SRG-APP-000342-MFP-000090,SRG-APP-000343-MFP-000091

Unauthorized changes to the zSecure baseline configuration could make the system vulnerable to various attacks or allow unauthorized access to the system. Changes to information system configurations can have unintended side effects, some of which may be relevant to security. Detecting such changes and providing an automated response can help avoid unintended, negative consequences that could ultimately affect the security state of the application. Examples of security responses include but are not limited to the following: halting application processing, halting selected application functions, or issuing alerts/notifications to organizational personnel when there is an unauthorized modification of a configuration item.

Previous versions of zSecure products and components that are not removed from the information system after updates have been installed may be exploited by adversaries. Some information technology products may remove older versions of software automatically from the information system.

Security flaws with software applications are discovered daily. Vendors are constantly updating and patching their products to address newly discovered security vulnerabilities. Organizations (including any contractor to the organization) are required to promptly install security-relevant software updates (e.g., patches, service packs, and hot fixes). Flaws discovered during security assessments, continuous monitoring, incident response activities, or information system error handling must also be addressed expeditiously.

The zSecure resource class that is configured for the zSecure access checks must be active to receive valid Allow/Deny responses from external security manager (ESM) resource checks. Activation is outside of zSecure, in the ESM.