Attributes of z/OS UNIX user accounts are not defined in accordance with security requirements.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-7050	ZUSS0048	SV-7940r2_rule	DCCS-1 DCCS-2	Medium

Description
RACF userids that use z/OS UNIX must be properly configured. If these attributes are not correctly defined, data access or command privilege controls could be compromised.

STIG	Date
z/OS RACF STIG	2015-06-24

Details

Check Text ( C-20795r1_chk )
a) Refer to the following report produced by the RACF Data Collection: - RACFCMDS.RPT(FACILITY) - RACFCMDS.RPT(LISTUSER) NOTE: This check only applies to the OMVS default user. If the OMVS default user is not defined in the Application Data field in the BPX.DEFAULT.USER resource in the FACILITY report, this is NOT APPLICABLE. b) If OMVS default user account is defined as follows, there is NO FINDING: 1) A unique UID number (except for UID(0) users) 2) A non-writable HOME directory 3) Shell program specified as “/bin/echo”, or “/bin/false” NOTE: The shell program must have one of the specified values. The HOME directory must have a value (i.e., not be allowed to default). c) If the user account is not defined as specified in (b) above, this is a FINDING.

Check Text ( C-20795r1_chk )

a) Refer to the following report produced by the RACF Data Collection:

- RACFCMDS.RPT(FACILITY)
- RACFCMDS.RPT(LISTUSER)

NOTE: This check only applies to the OMVS default user. If the OMVS default user is not defined in the Application Data field in the BPX.DEFAULT.USER resource in the FACILITY report, this is NOT APPLICABLE.

b) If OMVS default user account is defined as follows, there is NO FINDING:

1) A unique UID number (except for UID(0) users)
2) A non-writable HOME directory
3) Shell program specified as “/bin/echo”, or “/bin/false”

NOTE: The shell program must have one of the specified values. The HOME directory must have a value (i.e., not be allowed to default).

c) If the user account is not defined as specified in (b) above, this is a FINDING.

Fix Text (F-18752r1_fix)
- Use of the OMVS default UID will not be allowed on any classified system. - The definition of the OMVS default user will be restricted to a non-0 UID, a non-writable home directory, such as "\" root, and a non-executable, but existing, binary file, "/bin/false" or “/bin/echo.” - Collection of SMF type 80 records to track user access to OMVS default UID. The sample commands below show the required security parameters required for the default user: AG OEDFLTG SUPGROUP(ADMIN) OWNER(ADMIN) OMVS(GID(777777)) AU OEDFLTU DFLTGRP(OEDFLTG) NAME('OE DEFAULT USER') NOPASS - OMVS(UID(99999) HOME('/u/oeflt') PROGRAM('/bin/echo')) - DATA('DEFAULT OMVSUSERID ADDED WITH SOER5') RDEF FACILITY BPX.DEFAULT.USER APPLDATA('OEDFLTU/OEDFLTG') - DATA('ADDED TO SUPPORT THE DEFAULT USER') UACC(NONE) OWNER(ADMIN) SETR RACLIST(FACILITY) REFRESH

Fix Text (F-18752r1_fix)

- Use of the OMVS default UID will not be allowed on any classified system.

- The definition of the OMVS default user will be restricted to a non-0 UID, a non-writable home directory, such as "\" root, and a non-executable, but existing, binary file, "/bin/false" or “/bin/echo.”

- Collection of SMF type 80 records to track user access to OMVS default UID.

The sample commands below show the required security parameters required for the default user:

AG OEDFLTG SUPGROUP(ADMIN) OWNER(ADMIN) OMVS(GID(777777))
AU OEDFLTU DFLTGRP(OEDFLTG) NAME('OE DEFAULT USER') NOPASS -
OMVS(UID(99999) HOME('/u/oeflt') PROGRAM('/bin/echo')) -
DATA('DEFAULT OMVSUSERID ADDED WITH SOER5')
RDEF FACILITY BPX.DEFAULT.USER APPLDATA('OEDFLTU/OEDFLTG') -
DATA('ADDED TO SUPPORT THE DEFAULT USER') UACC(NONE) OWNER(ADMIN)
SETR RACLIST(FACILITY) REFRESH