Title

The VTAM USSTAB definitions are being used for unsecured terminals (Cat II impact)

Discussion

VTAM options and definitions are used to define VTAM operational capabilities. They must be strictly controlled. Unauthorized users could override or change start options or network definitions. Failure to properly control VTAM resources could potentially compromise the network operations.

Check Content

a) Have the IAO and VTAM Systems Programmer supply the following information: - Documentation regarding terminal naming standards. - Documentation of all procedures controlling terminal logons to the system. - A complete list of all USS commands used by terminal users to log on to the system. - Members and data set names containing USSTAB and LOGAPPL definitions of all terminals that can log on to the system (e.g., SYS1.VTAMLST). - Members and data set names containing logon mode parameters. b) If USSTAB definitions are only used for secure terminals (e.g., terminals that are locally attached to the host or connected to the host via secure leased lines), there is NO FINDING. c) If USSTAB definitions are used for any unsecured terminals (e.g., dial up terminals or terminals attached to the Internet such as TN3270 or KNET 3270 emulation), this is a FINDING.

Fix Text

The Systems programmer and IAO will verify that USSTAB definitions are only used for secure terminals. Only terminals that are locally attached to the host or connected to the host via secure leased lines located in a secured area. Only authorized personnel may enter the area where secure terminals are located. USSTAB or LOGAPPL definitions are used to control logon from secure terminals. These terminals can log on directly to any VTAM application (e.g., TSO, CICS, etc.) of their choice and bypass Session Manager services. Secure terminals are usually locally attached to the host or connected to the host via a private LAN without access to an external network. Only authorized personnel may enter the area where secure terminals are located.

Additional Identifiers

Rule ID: SV-7250r2_rule

Vulnerability ID: V-6949

Group Title: ZVTM0011

Expert Comments

CCIs tied to check.

Controls tied to check. These are derived from the CCIs shown above.