Unix System Services (USS) Review

Objective

The objective of this service offering is to provide technical consulting and review regarding the establishment of CA-Top Secret (TSS) mainframe security for the Unix Systems Services (USS) environment within IBM OS/390 release 2.6.  During a three to five man-day effort, a information security consultant familiar with the setup of TSS and USS security will review the steps already taken to establish security for the USS environment and will provide recommendations and knowledge transfer regarding the securing of this Unix environment. 

 

Specific areas in which Unix security will be examined include the following.  In each of these areas, actions already taken to provide security will be audited and recommendations will be made.

 

q       TSS setup for USS base Servers such as OMVS, INETD, BPXOINIT  

q       TSS setup of basic Unix Groups  (OMVSGRP, TTY)

q       Considerations surrounding the setup and maintenance of Unix Userids (UIDs)

q       TSS setup of basic Unix Superuser control

q       Considerations surrounding the setup of default Unix Profile for users

q       Security for base TCPIP and related servers (TCPIP, FTP, PORTD, SNMPD)

q       Security for optional Servers including the IBM Internet Web Server,  NFS/DFS, DCE, LDAP

 

Detailed Description of Services

 

q       TSS setup for USS base Servers

 

The setup of User ACIDs and Started-Task definitions with TSS will be reviewed and adjusted based upon recommendations and discussion.  USS base Servers include OMVS, INETD, and BPXOINIT.

 

Knowledge transfer will be performed to ensure that security reporting and monitoring practices are understood for this Unix environment.  Specifically, proper setup of the TSSOERPT utility report will be verified.  Also, use of the TSSUTIL and TSSTRACK utilities, as they pertain to Unix control, will be discussed.

 

q       TSS setup of basic Unix Groups

 

The philosophy for maintaining Unix Groups will be reviewed, discussed, and adjusted as agreed.  A minimum number of Unix Groups must be defined.  The proper setup of these Groups will be verified.

 

q       Considerations surrounding the setup and maintenance of Unix Userids (UIDs)

 

The procedures and philosophy for maintaining Unix Userids (UIDs) will be reviewed, discussed, and adjusted as agreed.  A moderate number of Unix userids must be defined for initial USS operation.  The proper setup of these userids will be verified.

 

q       TSS setup of basic Unix Superuser control

 

The procedures and philosophy for maintaining control for Unix “Super Users” will be reviewed, discussed, and adjusted as agreed.  In particular, the use of the securable “BPX.*” resources within the FACILITY resource class will be presented.

 

q       Considerations surrounding the setup of default Unix Profile for users

 

The optional capability to create a default profile for users access of this Unix environment will be reviewed and discussed.  The complexity of allowing end-user FTP access, while not allowing, other Unix environment access will be presented.

 

q       Security for base TCPIP and related servers (TCPIP, FTP, PORTD, SNMPD)

 

Likely the most important area to be reviewed and discussed regards the TCPIP service.  This service is the gateway by which remote, network access, is made to this Unix environment.  The setup of security for base TCPIP servers will be verified.  More importantly, the limitations of mainframe security over Unix applications commonly accessible via TCPIP will be presented.  The need to consider application security controls in Unix applications such as the IBM Web Server will be emphasized.

 

q       Security for optional Servers including the IBM Internet Web Server, NFS/DFS, DCE, LDAP

 

The setup of User ACIDs and Started-Task definitions within TSS for these servers will be reviewed and adjusted based upon recommendations and discussion.