HP OpenVMS Systems Documentation
OpenVMS Guide to System Security
3.5.1 Using a Terminal That Requires a System Password
You cannot log in if the terminal you attempt to use requires a system password and you are unaware of the requirement. All attempts at logging in fail until you enter the system password.
If you know the system password, perform the steps described in Section 3.2.1. If your attempts fail, it is possible that the system password has been changed. Move to a different terminal that does not require a system password, or request the new system password.
If you do not know the system password and you suspect that this is the
problem, try logging in at another terminal.
If you attempt a class of login that is prohibited in your UAF record, your login fails. For example, your security administrator can restrict you from logging in over the network. If you attempt a network login, you receive a message stating that you are not authorized to log in from this source.
Your security administrator can restrict your logins to include or
exclude any of the following classes: local, remote, dialup, batch, or
network. (For a description of these classes, see Section 3.4.1 and
Another cause of login difficulty is failure to observe your shift restrictions. A system manager or security administrator can control access to the system based on the time of day or the day of the week. These restrictions are imposed on classes of logins. The security administrator can apply the same work-time restrictions to all classes of logins or choose to place different restrictions on different login classes. If you attempt a login during a time prohibited for that login class, your login fails. The system notifies you that you are not authorized to log in at this time.
When shift restrictions apply to batch jobs, jobs you submit that are
scheduled to run outside your permitted work times are not run. The
system does not automatically resubmit such jobs during your next
available permitted work time. Similarly, if you have initiated any
kind of job and attempt to run it beyond your permitted time periods,
the job controller aborts the uncompleted job when the end of your
allocated work shift is reached. This job termination behavior applies
to all jobs.
If your login fails and you have attempts remaining, press the Return key and try again. You can do this until you succeed or reach the limit. If the connection is lost, you can redial the access line and start again.
The typical reason for limiting the number of dialup login failures is
to discourage unauthorized users attempting to learn passwords by trial
and error. They already have the advantage of anonymity because of the
dialup line. Of course, limiting the number of tries for each dialup
does not necessarily stop this kind of intrusion. It only requires the
would-be perpetrator to redial and start another login.
If anyone has made a number of failed attempts to log in at the same terminal with your user name, the system concludes that an intruder is attempting to gain illegal access to the system by using your user name.
At the discretion of your security administrator, break-in evasion measures can be in effect for all users of the system. The security administrator controls how many password attempts are allowed over what period of time. Once break-in evasion tactics are triggered, you cannot log in to the terminal---even with your correct password---during a defined interval. Your security administrator can tell you how long you must wait before reattempting the login, or you can move to another terminal to attempt a login.
If you suspect that break-in evasion is preventing your login and you
have not personally experienced any login failures, you should contact
your security administrator immediately. Together, you should attempt
another login and check the message that reveals the number of login
failures since the last login to confirm or deny your suspicion of
intrusion attempts. (If your system does not normally display the login
message, your security administrator can use the Authorize utility
(AUTHORIZE) to examine the data in your UAF record.) With prompt
action, your security administrator can locate someone attempting
logins at another terminal.
Changing passwords on a regular basis promotes system security. To change your password, enter the DCL command SET PASSWORD.
The system manager can allow you to select a password on your own or can require that you use the automatic password generator when you change your password. If you select your own password, note that the password must follow system restrictions on length and acceptability (see Section 3.1.2). For example, if your password choice is too short, the system displays the following message:
Section 3.1 provides guidelines and examples for specifying secure passwords.
There is no restriction on how many times you can change your password
in a given period of time.
If your system manager does not require use of the automatic password generator, the SET PASSWORD command prompts you to enter the new password. It then prompts you to reenter the new password for verification, as follows:
If you fail to enter the same password twice, the password is not changed. If you succeed in these two steps, there is no notification. The command changes your password and returns you to the DCL prompt.
Even though your security administrator may not require the password
generator, you are strongly encouraged to use it to promote the
security of your system. Section 3.6.2 describes how to use generated
If your system security administrator decides that you must let the system generate the password for you automatically, the system provides you with a list of password choices when you enter the DCL command SET PASSWORD. (When the system does not require generated passwords, add the /GENERATE qualifier to SET PASSWORD for a list of password choices.) The character sequence resembles native language words to make it easy to remember, but it is unusual enough to be difficult for outsiders to guess. Because system-generated passwords vary in length, they become even more difficult to guess.
In the following OpenVMS VAX example, the system automatically generates a list of passwords made up of random sequences of characters. The minimum password length for the user in the following example has been set to 8 in the UAF record.
The preceding example illustrates the following:
One disadvantage of automatic password generation is the possibility that you might not remember your password choice. However, if you dislike all the password choices in your list or think none are easy to remember, you can always request another list.
A more serious drawback of automatic password generation is the potential disclosure of password choices from the display the command produces. To protect your account, change your password in private. If you perform the change on a video terminal, clear the display of password choices from the screen after the command finishes. If you perform the change in a DECwindows environment, use the Clear Lines Off Top option from the Commands menu to remove the passwords from the screen recall buffer. If you use a printing terminal, properly dispose of all hardcopy output.
If you later realize that you failed to protect your password in these
ways, change your password immediately. Depending on site policy or
your own judgment concerning the length of time your account was
exposed, you might decide to notify your security administrator that a
security breach could have occurred through your account.
To change a secondary password, use the DCL command SET PASSWORD/SECONDARY. You are prompted to specify the old secondary password and the new secondary password, just as in the procedure for changing the primary password. To remove a secondary password, press the Return key when you are prompted for a new password and verification.
You can change primary and secondary passwords independently, but both
are subject to the same change frequency because they share the same
password lifetime. See Section 3.7 for information on password
Even if your current password has not yet expired, you can change your password when you log in to the system by including the /NEW_PASSWORD qualifier with your user name, as follows:
Entering the /NEW_PASSWORD qualifier after your user name forces you to
set a new password immediately after login.
Your system manager can set up your account so that your password, or
the account itself, expires automatically on a particular date and
time. Password expiration times promote system security by forcing you
to change your password on a regular basis. Account expiration times
help to ensure that accounts are available only for as long as they are
As you approach the expiration time of your password, you receive an advance warning message. The message first appears 5 days before the expiration date and at each subsequent login. The message appears immediately below the new mail message and sounds the bell character on your terminal to attract your attention. The message indicates that your password is expiring, as follows:
If you fail to change your password before it expires, you receive the following message when you log in:
The system prompts you for a new password or, if automatic password generation is enabled, asks you to select a new password from those listed (see Section 3.6.2). You can abort the login by pressing Ctrl/Y. At your next login attempt, the system again prompts you to change your password.
If secondary passwords are in effect for your account (see Section 3.2), the secondary password may expire at the same time as the primary one. You are prompted to change both passwords. If you change the primary password and press Ctrl/Y before changing the secondary password, the login fails. The system does not record a password change.
If the system manager decides not to force you to change your expired password upon logging in, you receive one final warning when you log in after your password expires, as follows:
At this point, if you do not change the password or if the system fails
before you have the opportunity to do so, you will be unable to log in
again. To regain access, see your system manager.
If you need your account for a specific purpose for a limited time only, the person who creates your account may specify a period of time after which the account lapses. For example, student accounts at universities are typically authorized for a single semester at a time.
The system automatically denies access to expired accounts. You receive no advance warning message before the account expiration date, so it is important to know in advance your account duration. The account expiration resides in the UAF record, which can be accessed and displayed only through the use of the Authorize utility (AUTHORIZE) by users with the SYSPRV privilege or equivalent---normally, your system manager or security administrator.
When your account expires, you receive an authorization failure message
at your next attempted login. If you need an extension, follow the
procedures defined at your site.
Illegal system access through the use of a known password is most often caused by the owner's disclosing the password. It is vital that you do not reveal your password to anyone.
You can best protect your password by observing the following rules:
3.9 Network Security Considerations
This section describes how to use access control strings in file
specifications and how to use proxy logins to help make network access
Network access control strings can be included in the file specifications of DCL commands working across the DECnet for OpenVMS network. They permit a user on a local node to access a file on a remote node.
An access control string consists of the user name for the remote account and the user's password enclosed within quotation marks, as follows:
Because access control strings include sufficient information to allow someone to break in to the remote account, they create serious security exposure. To protect access control string information, do the following:
To avoid the need for access control strings, you might prefer to use proxy login accounts, which are described in Section 3.9.2.