STIGQter: STIG Summary: IBM z/OS RACF Security Technical Implementation Guide Version: 8 Release: 3 Benchmark Date: 23 Apr 2021:

IBM z/OS TCP/IP resources must be properly protected.

DISA Rule

SV-223823r604139_rule

Vulnerability Number

V-223823

Group Title

SRG-OS-000080-GPOS-00048

Rule Version

RACF-TC-000040

Severity

CAT II

CCI(s)

• CCI-000213 - The information system enforces approved authorizations for logical access to information and system resources in accordance with applicable access control policies.

Weight

10

Fix Recommendation

Develop a plan of action to implement the required changes. Ensure the following items are in effect for TCP/IP resources.

(Note: The resource class, resources, and/or resource prefixes identified below are examples of a possible installation. The actual resource class, resources, and/or resource prefixes are determined when the product is actually installed on a system through the product’s installation guide and can be site specific.)

Ensure that the EZA, EZB and IST resources and/or generic equivalent are defined to the SERVAUTH resource class with a UACC(NONE).

No access is given to the EZA, EZB, and IST resources of the SERVAUTH resource class.

If the product CSSMTP is on the system, no access is given to EZB.CSSMTP of the SERVAUTH resource class. EZB.CSSMTP.sysname.writername.JESnode will be specified and made available to the CSSMTP started task and authenticated users that require access to use CSSMTP for e-mail services.

Only authenticated users that require access are permitted access to the second level of the resources in the SERVAUTH resource class. Examples are the network (NETACCESS), port (PORTACCESS), stack (STACKACCESS), and FTP resources in the SERVAUTH resource class.

The EZB.STACKACCESS. resource access authorizations restrict access to those started tasks with valid requirements and users with valid FTP access requirements.

The EZB.FTP.*.*.ACCESS.HFS) resource access authorizations restrict access to FTP users with specific written documentation showing a valid requirement exists to access OMVS files and Directories.

The following commands are provided as a sample for implementing resource controls:

RDEF SERVAUTH EZB.** UACC(NONE) OWNER(ADMIN) AUDIT(FAILURE(READ))
RDEF SERVAUTH EZB.CSSMTP.** UACC(NONE) OWNER(ADMIN) AUDIT(FAILURE(READ))
RDEF SERVAUTH EZB.CSSMTP.sysname.writername.JESnode UACC(NONE) OWNER(ADMIN) AUDIT(FAILURE(READ))
RDEF SERVAUTH EZB.FTP.** UACC(NONE) OWNER(ADMIN) AUDIT(FAILURE(READ))
RDEF SERVAUTH EZB.NETACCESS.** UACC(NONE) OWNER(ADMIN) AUDIT(FAILURE(READ))
RDEF SERVAUTH EZB.PORTACCESS.** UACC(NONE) OWNER(ADMIN) AUDIT(FAILURE(READ))
RDEF SERVAUTH EZB.STACKACCESS.** UACC(NONE) OWNER(ADMIN) AUDIT(FAILURE(READ))

PE EZB.CSSMTP.sysname.writername.JESnode CL(SERVAUTH) ID(authusers) ACC(READ)
PE EZB.FTP.** CL(SERVAUTH) ID(authusers) ACC(READ)
PE EZB.FTP.sysname.ftpstc.ACCESS.HFS CL(SERVAUTH) ID(ftpprofile) ACC(READ)
PE EZB.NETACCESS.** CL(SERVAUTH) ID(authusers) ACC(READ)
PE EZB.PORTACCESS.** CL(SERVAUTH) ID(authusers) ACC(READ)
PE EZB.STACKACCESS.** CL(SERVAUTH) ID(authusers) ACC(READ)
PE EZB.STACKACCESS.sysname.TCPIP CL(SERVAUTH) ID(ftpprofile) ACC(READ)

The following notes apply to these controls:

- EZB.STACKACCESS.sysname.TCPIP access READ should be limited to only those started tasks that require access to the TCPIP Stack as well as any users approved for FTP Access (inbound and/or outbound). FTP users should not have access to the EZB.FTP.sysname.ftpstc.ACCESS.HFS resource unless specific written justification documenting valid requirement for those FTP users to access USS files and directories via FTP.

- To be effective in restricting access, the network (EZB.NETACCESS) resource control requires configuration of the NETACCESS statement in the PROFILE.TCPIP file.

- To be effective in restricting access, the port (EZB.PORTACCESS) resource control requires configuration of a PORT or PORTRANGE statement in the PROFILE.TCPIP file. These port definitions within PROFILE.TCPIP must be defined to include SAF keyword and a valid name.

A list of possible SERVAUTH resources defined to the first two nodes is shown here: (Note that additional resources may be developed with each new release of TCPIP.)

EZA.DCAS.
EZB.BINDDVIPARANGE.
EZB.CIMPROV.
EZB.FRCAACCESS.
EZB.FTP.
EZB.INITSTACK.
EZB.IOCTL.
EZB.IPSECCMD.
EZB.MODDVIPA.
EZB.NETACCESS.
EZB.NETMGMT.
EZB.NETSTAT.
EZB.NSS.
EZB.NSSCERT.
EZB.OSM.
EZB.PAGENT.
EZB.PORTACCESS.
EZB.RPCBIND.
EZB.SOCKOPT.
EZB.SNMPAGENT.
EZB.STACKACCESS.
EZB.TN3270.
IST.NETMGMT.

Check Contents

From the ISPF Command Shell enter:
RLIST SERVAUTH * ALL

If the following guidance is true, this is not a finding.

The EZA, EZB, and IST resources and/or generic equivalent are defined to the SERVAUTH resource class with a UACC(NONE).

No access is given to the EZA, EZB, and IST high level resources of the SERVAUTH resource class.

If the product CSSMTP is on the system, no access is given to EZB.CSSMTP of the SERVAUTH resource class.

If the product CSSMTP is on the system, EZB.CSSMTP.sysname.writername.JESnode will be specified and made available to the CSSMTP started task and authenticated users that require access to use CSSMTP for e-mail services.

Authenticated users that require access will be permitted access to the second level of the resources in the SERVAUTH resource class. Examples are the network (NETACCESS), port (PORTACCESS), stack (STACKACCESS), and FTP resources in the SERVAUTH resource class.

The EZB.STACKACCESS. resource access authorizations restrict access to those started tasks with valid requirements and users with valid FTP access requirements.

The EZB.FTP.*.*.ACCESS.HFS) resource access authorizations restrict access to FTP users with specific written documentation showing a valid requirement exists to access OMVS files and Directories.

Vulnerability Number

V-223823

Documentable

False

Rule Version

RACF-TC-000040

Severity Override Guidance

From the ISPF Command Shell enter:
RLIST SERVAUTH * ALL

If the following guidance is true, this is not a finding.

The EZA, EZB, and IST resources and/or generic equivalent are defined to the SERVAUTH resource class with a UACC(NONE).

No access is given to the EZA, EZB, and IST high level resources of the SERVAUTH resource class.

If the product CSSMTP is on the system, no access is given to EZB.CSSMTP of the SERVAUTH resource class.

If the product CSSMTP is on the system, EZB.CSSMTP.sysname.writername.JESnode will be specified and made available to the CSSMTP started task and authenticated users that require access to use CSSMTP for e-mail services.

Authenticated users that require access will be permitted access to the second level of the resources in the SERVAUTH resource class. Examples are the network (NETACCESS), port (PORTACCESS), stack (STACKACCESS), and FTP resources in the SERVAUTH resource class.

The EZB.STACKACCESS. resource access authorizations restrict access to those started tasks with valid requirements and users with valid FTP access requirements.

The EZB.FTP.*.*.ACCESS.HFS) resource access authorizations restrict access to FTP users with specific written documentation showing a valid requirement exists to access OMVS files and Directories.

Check Content Reference

M

Target Key

4101

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