HP OpenVMS Guide to System Security > Chapter 7 Managing System Access

Defining Times and Conditions for System Access

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The level of system access a user enjoys depends on your site requirements, that user's role in the organization, and your management of his or her account. A site with low security requirements and plenty of system resources may allow access at any time of day whereas a site with moderate security requirements may limit logins to daytime hours and permit dialup or network connections only to a subset of users.

Using the Authorize utility, you control when and how users can access the system. Table 7-1 “Authorize Qualifiers Controlling Login Times and Conditions” identifies the applicable qualifiers.

Table 7-1 Authorize Qualifiers Controlling Login Times and Conditions

Categories Qaulifier Description

Time of day

/ACCESS

By default, a user has full access every day. By specifying an access time, you prevent access at all other times. Identify hours on primary days with the keyword PRIMARY; identify hours on secondary days with the keyword SECONDARY.

 

/DIALUP

Specifies hours of access permitted for dialup logins.

 

/LOCAL

Specifies hours of access for interactive logins from local terminals.

Days of week

/PRIMEDAYS

Defines the primary and secondary days of the week for logging in.

Mode of operation

/BATCH

Specifies the hours of access permitted for batch jobs.

 

/INTERACTIVE

Specifies the hours of access for interactive logins.

 

/NETWORK

Specifies the hours of access permitted for network batch jobs.

 

/REMOTE

Specifies hours during which access is permitted for interactive logins from network remote terminals (with the DCL command SET HOST).

Allocation of resources

/DEVICE

Specifies the name of the user's default device at login.

 

/DIRECTORY

Specifies the name of the user's default directory at login.

Validity of account

/EXPIRATION

Specifies the expiration date and time of the account.

 

/FLAGS=DISUSER

Disables the account so the user cannot log in.

External authentication

/FLAGS=EXTAUTH

Specifies that the user is externally authenticated.

 

Restricting Work Times

AUTHORIZE qualifiers let you restrict system use to certain days of the week and certain periods of the day. Restricting work times is useful to better balance the workload on your system. Restricting access to accounts is also an effective way of preventing unauthorized use of the system outside of normal working hours.

Define primary and secondary days of the week with the /PRIMEDAYS qualifier, or conform to the default where primary days are Monday through Friday and secondary days are Saturday and Sunday. For example, to modify the defaults for a user who works Tuesday through Saturday, you would specify the /PRIMEDAYS qualifier as follows:

/PRIMEDAYS=(NOMONDAY,TUESDAY,WEDNESDAY,THURSDAY,FRIDAY,SATURDAY,NOSUNDAY)

Occasionally an operational change occurs that conflicts with the normal day assignments at your site, such as a holiday falling on a primary day. To override the normal day assignment, use the DCL command SET DAY, and specify the day-type interpretation you want for the current day. This requires OPER privilege. Note that this change applies to all logged-in users, as well as those who will log in during the day. If users who are currently logged in are unauthorized for the day-type once it changes, they are logged out of the system at the next hour. (The job controller enforces time restrictions on an hourly basis.)

Decide which types of login access should be restricted to certain hours. The login access qualifiers are: /LOCAL, /REMOTE, /DIALUP, /INTERACTIVE, /BATCH, and /NETWORK. However, if your site applies one set of primary and secondary hours for all types of logins, you can specify the /ACCESS qualifier, which applies to all modes of access.

The following example shows how to apply the /BATCH qualifier to a user's account to disable the user from running batch jobs during normal working hours:

/NOBATCH=(PRIMARY, 9-17)

This specification permits the user to run batch jobs only during the hours of 6:00 p.m. through 8:59 a.m. on primary days but all day on secondary days.

Restricting Modes of Operation

The following concerns might cause you to prohibit network access for some of your users:

  • The user has data that should be accessed only through the local node.

  • Penetration attempts are more likely to occur over a network because of the increased anonymity of the connection. (This concern is also relevant to dialup connections.)

Use the AUTHORIZE qualifier /NONETWORK to prevent specific users from having network access, as shown in the following example:

UAF> ADD JSMITH /NONETWORK, ...

Any of the AUTHORIZE access mode qualifiers (/LOCAL, /REMOTE, /DIALUP, /INTERACTIVE, /BATCH, or /NETWORK) can be negated in this manner to restrict access to the system.

Restricting Account Duration

It is good practice to set an account expiration time that matches the maximum length of time you expect the user to require access. When the expiration time arrives, the system automatically prohibits access to the account. You must still remove the UAF record and delete the user's files.

Use of the /EXPIRATION qualifier also forces you to periodically review accounts and reauthorize only those that are necessary.

To set the account expiration time, use the AUTHORIZE qualifier /EXPIRATION in the user's UAF record. For example, the following qualifier specifies that the user's account will expire on the 30th of December 2001:

/EXPIRATION=30-DEC-2001

Disabling Accounts

You may want to severely restrict the use of certain accounts. For example, you may want to disable specific accounts used only periodically, such as the SYSTEST and FIELD accounts, to limit possible misuse of these accounts. Disable the accounts with the /FLAGS=DISUSER qualifier. Temporarily enable the accounts with the /FLAGS=NODISUSER qualifier when needed.

Restricting Disk Volumes

Identify the user's default device and directory in the UAF record with the AUTHORIZE qualifiers /DEVICE and /DIRECTORY. You can limit the number of blocks available to the user on that disk (and any other disk) through the disk quota feature of the System Management utility (SYSMAN), as described in the HP OpenVMS System Management Utilities Reference Manual: A-L.

The volume protection in place on other disks controls how much access a user can obtain to the disks. The user's privileges, which can be extended or limited through the AUTHORIZE qualifier /PRIVILEGES, also influence the access available (see “Giving Users Privileges”).

Marking Accounts for External Authentication

Mark a user's account in the UAF record with the AUTHORIZE qualifier /FLAGS=EXTAUTH to allow the user to be externally authenticated.

See “Enabling External Authentication” for more information.