Updated: 11 December 1998

OpenVMS Guide to System Security

The files comprising the TCB are correctly protected when the operating system is installed; however, the protection can be altered by sufficiently privileged users. Appendix B of this guide describes the correct file protection of operating system files.

When installing an OpenVMS operating system, avoid modifying any system files except those specific to your site. You want to maintain the security of the base operating system.

C.4.2 Privileges for Trusted Users

Certain privileges allow the holder to bypass normal file and memory access controls directly or indirectly and, therefore, must not be granted to persons other than the system manager, security administrator, or other trusted users. Privileges in four categories are appropriate only for trusted users: Objects, All, System, and Group. Refer to Table 8-2 for the privileges belonging to each of these categories. The privileges themselves are described in detail in Appendix A.

Privileges in the Objects and All categories allow the holder to violate the isolation of the TCB from untrusted users. Privileges in the System category allow the holder to interfere with normal system operation and cause denial of service, but they do not allow the holder to actually violate object access controls. Some privileges in the System category also allow access controls to be ultimately bypassed.

Privileges in the Group category permit the holder to interfere with the operations of others in the same group. The GRPPRV privilege, in particular, permits the holder to violate normal access controls within that holder's group because it grants access (through the system field of the protection code) to objects owned by subjects sharing the same group UIC.

All trusted users should be familiar with all the effects of any operations they perform. In particular, they need to know all software products an operation might use because a trusted user's privileges can allow untrusted software to perform operations that OpenVMS security policy would otherwise preclude.

C.4.3 Privileges for Untrusted Users

Untrusted users can hold any privilege in the Normal and Devour category with the exception of GRPNAM. Exercise caution in granting privileges from the Devour category, however, for they permit the holder to consume resources without limit, thereby causing possible denial of service and interference with the operations of other users on the system. Table C-2 lists privileges allowed to untrusted users.

Table C-2 Privileges for Untrusted Users

Category	Privilege	Activity Permitted
Normal	NETMBX TMPMBX	Create network connections Create temporary mailbox
Devour	ACNT ALLSPOOL BUGCHK EXQUOTA PRMCEB PRMGBL PRMMBX SHMEM	Disable accounting Allocate spooled devices Make bugcheck error log entries Exceed disk quotas Create/delete permanent common event flag clusters Create permanent global sections Create permanent mailboxes Create/delete structures in shared memory

C.4.4 Physical Security

Physical and environmental security are critical to the secure operation of the system. All physical components of the TCB require adequate protection, or unauthorized people can jeopardize the system's security. Because the following practices and features jeopardize the security of the TCB, they must not be used in a C2 environment:

• Do not put the console terminal in a public area. The console terminal must always be physically secured because it controls operation of the CPU and, consequently, operation of the system.
• Do not leave the console password disabled if the console has the password feature. (It is available on some VAXstation 3100s, most later models, and the evaluated Alpha models.) The console password prevents unauthorized personnel from using commands to boot from alternate media, to perform a conversational boot, or to modify memory.
• Do not allow modems. Modems provide an avenue into the trusted system, and the possibilities for compromising system security are enormous.
• Do not leave remote diagnostics enabled. Remote diagnostics provide another avenue into the trusted system. Disable remote diagnostics by placing the diagnostics switch in the off position.
• Do not allow authentication cards. These devices are not supported in a C2 evaluated configuration.
• Do not permit physical access to cluster communication media. Intruders can penetrate the system if they have physical access to any processor or cable.
  The operating system protects all communications interfaces against world access by default. This includes the CI and local area network (LAN) devices, such as the Ethernet, DSSI, FDDI, and SCSI. The CI interface is a trusted interface among members of a CI cluster and is inaccessible to unprivileged users. Unprivileged users should not be granted access to LAN devices.
• Do not allow untrusted users to access the HSC console. Place the console in an area where only authorized personnel can use it. You do not want untrusted users to perform sensitive operations, such as backing up and restoring disk volumes.
• Do not allow users to read printer output of other users. Protect printer output so users have access only to their own data.
• Do not leave storage media, such as disks, tapes, and compact discs, where unauthorized users can access it. Once a user has the media in their possession, they can read and modify its contents.

This section discusses C2 constraints on the use of OpenVMS features. It includes the following topics:

• Requirements for maintaining individual accountability
• Correct management of the audit log file
• Correct use of terminals, volumes, and printers
• Cluster requirements
• Required settings for system parameters
• Commands and software excluded from system operation

The proper use of names, UICs, and passwords ensures that individual accountability is enforced by the OpenVMS operating system. As a general practice, Compaq recommends that you use generated passwords on privileged accounts. Because the following practices and features result in the loss of individual accountability, they must not be used in a C2 environment:

• Do not assign the same UIC to more than one user. The UIC is used as the universal internal user identifier; therefore, unique UICs must be assigned to all users.
• Do not allow open accounts. Lack of a password makes an account available to all users aware of its identity. The system manager can prevent open accounts by never setting null passwords with the Authorize utility (AUTHORIZE) and by ensuring that all accounts are set up with a nonzero minimum password length.
• Do not allow group accounts. Individual accountability is lost when more than one person shares an account. Each user must be given a unique account.
• Do not allow guest accounts because they allow multiple users access to resources on your system through a common account. Most needs for a guest account can be handled by special proxy login accounts.
• Do not enable autologin. The automatic login facility (ALF) associates an account with a particular terminal instead of a particular person and, therefore, causes a loss of individual accountability.
• Do not initiate network proxy accounts for groups. In order to preserve individual accountability, each individual in a network must be given a unique network proxy account on each node to which that user has access. Assign the same user name and UIC on all applicable nodes, and then set up individual proxies among the corresponding accounts.
• Do not grant privileged access to proxy accounts.
• Do not grant the DBG$ENABLE_SERVER identifer in the rights database unless it is needed to run the debug server.
• Do not log operator HSC activities to a video terminal. You must use a hardcopy printer to log operator activities so it is possible to associate a specific system operation with the person performing it.
• Ensure users are familiar with the restrictions on the use of access control strings in the evaluated configuration. (See page 3-15 in the SFUG.) Specifically, the use of access control strings is not permitted in an evaluated configuration. The proxy login accounts should be used in the evaluated configuration.
• Do not allow operators to perform any task from the HSC console without signing the operator log. The sign-in log is required to track who performed HSC console operations and when. Together with the hardcopy output, the log provides a record of HSC operations.

The security-auditing system lets you to track security-relevant activity on the system provided you manage it correctly. To follow a trail of activity in the audit logs, you must have complete and accurate records. Security event messages can be recorded in the security audit log file and on any terminal designated to receive security-class event messages. Because the following practices jeopardize a site's ability to track security-relevant events in the system, they must not be used in a C2 environment:

• Do not disable the audit server or OPCOM. The audit server must be running to process audit event messages, and OPCOM is required to deliver alarms.
• Do not use multiple audit log files in a cluster. You must use the clusterwide audit log file, which the system establishes by default. Without this clusterwide file, it is difficult to show the precise relationship among events that occur on various cluster nodes during any given time period.
• Do not use a video terminal as a security operator terminal. You must enable a hardcopy terminal to receive security event messages.
• Do not place the security operator terminal in a public location. Physically secure the terminal so that only authorized personnel have access to it.
• Do not ignore the audit log file. You must review the security audit log file regularly for all audit events. In particular, notice whether any auditing modifications have been made. (Any use of the SET AUDIT command indicates some modification has taken place.) The audit log file is normally protected against reading or modification by unauthorized users.
• Do not allow tampering with the audit log file. Alway place security-auditing ACEs on the system security audit log file to enable auditing of all attempts to modify or delete the audit log file.
  For example:

  $ SET SECURITY SYS$MANAGER:SECURITY.AUDIT$JOURNAL - _$ /ACL=((ALARM=SECURITY,ACCESS=WRITE+DELETE+CONTROL+SUCCESS+FAILURE),- _$ (AUDIT=SECURITY,ACCESS=WRITE+DELETE+CONTROL+SUCCESS+FAILURE))

  The operating system audits ACL events by default, and you can verify this setting with the DCL command SHOW AUDIT. If necessary, reenable ACL alarms and audits with the following command:

  $ SET AUDIT/ALARM/AUDIT/ENABLE=ACL

• Do not allow trusted users to operate without supervision. You should audit the actions of trusted users (such as operators, managers, and security administrators) by enabling auditing of changes to the authorization database. Also place security-auditing ACEs on captive login command procedures and the directories containing them so you can detect modifications.

Before allocating memory or protected objects like volumes and devices to new users, sites must ensure that they are free of old data. The memory management subsystem protects against the reuse of system memory pages, and it cannot be defeated. Because the following practices jeopardize the clearing of old data from volumes and terminals before reallocation, they must not be followed in a C2 environment:

• Do not disable high-water marking on system disk volumes. The high-water marking and erase-on-delete features of the operating system protect against reuse of disk blocks (see Section 8.9.5).
• Do not allow users to leave their terminals on after logging out. They must turn off their terminals so the logout message is erased. The logout message reveals a user name and sometimes a node name. Moreover, by turning off the terminal, terminal characteristics are reset, and memory buffers are cleared. Some Trojan horse attacks use hardware frame buffers and the answerback capabilities that are built into newer terminals.
• Do not recycle tape volumes to new users until the tapes have been erased externally by operations personnel. The operating system provides no protection against reuse of tape volumes. (This is because the OpenVMS operating system considers tape drives to be single-user devices. It provides tape protection only at the volume level; an entire volume can be assigned ownership and protection but individual files on the volume cannot.)

Compaq recommends that sites clear printers between jobs to ensure that print jobs do not interfere with one another. A security administrator can reset printers automatically at the start or end (or both) of each job by associating a device control library with the print queue. Consult the documentation supplied with your printer to determine the appropriate reset sequence, and then refer to the OpenVMS System Manager's Manual for directions on adding that sequence to a library and associating the library with the queue.

C.5.4 Configuring Clusters

All valid cluster configurations, when configured as common environment clusters, fully support the OpenVMS security features. Because the following practices and features result in the loss of a common environment cluster, they must not be used in a C2 environment.

• Do not operate with multiple authorization databases or audit log files. A clustered system is considered a single security and management domain and must operate with a shared authorization database and a single audit log file. If you have multiple system disks for performance reasons, system managers should ensure that the system files are identical.
  The following files must be shared across all cluster members:

  NETOBJECT.DAT	NET$PROXY.DAT
  NETPROXY.DAT	QMAN$MASTER.DAT
  RIGHTSLIST.DAT	SYS$QUEUE_MANAGER.QMAN$QUEUES
  SYSUAF.DAT	SYSUAFALT.DAT
  VMS$AUDIT_SERVER.DAT	VMSMAIL_PROFILE.DATA
  VMS$OBJECTS.DAT	VMS$PASSWORD_DICTIONARY.DATA
  VMS$PASSWORD_HISTORY.DATA	VMS$PASSWORD_POLICY.EXE

• Do not attach nodes to the cluster that are not part of the evaluated system. The evaluated OpenVMS configuration includes DECnet software bounded to the cluster environment that is a single security domain. All physically attached nodes must be part of the evaluated system.

A C2 system is the shipped system that has been configured according to the guidelines in this appendix. When configuring your system, you must observe the following guidelines:

• Set security-sensitive parameters to the following values:

  System Parameter	Setting	Description
  LGI_CALLOUTS	0	Disables use of LOGINOUT callouts
  LOAD_PWD_POLICY	0	Disables site-specific password filters
  MAXSYSGROUP	7	Sets the maximum UIC value for the system category to single-digit UICs
  NISCS_CONV_BOOT	0	Disables use of a conversational system bootstrap
  RMS_FILEPROT	65,280	Sets a default protection code for user's files of S:RWED,O:RWED,G,W
  SECURITY_POLICY	0	Disables certain unevaluated operating system components
  STARTUP_P1	" "	Disables the minimum sequence of the startup procedure

• Do not use the CONNECT CONSOLE command to connect to a console storage device, except on a VAX 9000 system. On a VAX 9000 system, use the console command SET SPU_UPDATE OFF to isolate the storage device. Some console subsystems support a storage device, such as a tape or disk, that is used to load system and diagnostic programs; however, the operating system also supports the capability to read and write data on a console storage device, so it is neccessary to isolate the console storage device from the system. This command is not available on the evaluated Alpha platforms.
• Do not enable console operations by booting with FYDRIVER. FYDRIVER would make two DCL commands operative:
  • SET HOST/HSC allows a user to initiate certain HSC console operations from an OpenVMS node
  • SET HOST/DUP is used for configuring DSSI devices
  
  If you need to install FYDRIVER during system startup to configure your HSC devices and disks or perform necessary diagnostics, then perform a minimum boot and install FYDRIVER so you can configure devices and so on. Then shut down the system and reboot without FYDRIVER.

A system or security administrator may force an untrusted subject to reauthenticate himself or herself at any time. This might be necessary when the subject's access rights have been modified. The procedure is as follows and can be performed only by a trusted subject.

1. Make the changes to the subject's authorization record in the authorization file.
2. Obtain the owner's UIC of the subject from the authorization file.
3. Enter the SYSMAN utility.
4. Use the SYSMAN utility to identify all processes owned by the subject.
   1. In an OpenVMS Cluster environment, set the SYSMAN environment clusterwide. If you are not in an OpenVMS Cluster environment, skip this step.
   2. Use SYSMAN DO SHOW SYSTEM/FULL to obtain a listing of all processes on the system or OpenVMS cluster. This command also lists the owner UIC and system PID of each process. Record this information.
5. From SYSMAN, stop every process on every system that is owned by the subject.
   Note: Any process created by the subject after Step 4 is bound by the new access rights and does not need to be deleted. Therefore, this is not a recursive procedure.
   1. In the OpenVMS cluster environment, set the SYSMAN environment to point to only one node. If you are not in the OpenVMS cluster environment, skip this step.
   2. For each process on the system to be deleted, identify the PID from Step 2 and use the SYSMAN DO STOP/ID=pid command to stop the job.
   3. Repeat Steps a and b until all desired processes on all nodes of the cluster have been stopped.

The previous sections of this appendix describe the U.S. government requirements for running the OpenVMS operating system in a C2 environment. The following list reviews the government's security requirements:

Installing the System

• Did you perform a full installation (not an upgrade) as described in the OpenVMS VAX Version 6.1 Upgrade and Installation Manual?

Using Evaluated Components

• Is all hardware in your configuration listed on the evaluated hardware list? (See Final Evaluation Report, Compaq Equipment Corporation, OpenVMS VAX and SEVMS Version 6.0.)
• Have you excluded the following software products: DECdns, LASTport, LASTport/DISK, LAT?
• Do system files have the same protection as when Compaq delivered them to you? (See Appendix B.)
• Did you avoid installing DECwindows software or other privileged layered products?

Making Individuals Accountable

• Have you trained privileged users so they understand the effect of operations they may perform?
• Does each user have a unique UIC?
• Do all accounts have passwords of nonzero length?
• Does each user have a separate account?
• Have you eliminated any guest accounts?
• Have you disabled all autologins?
• Does each user have a unique proxy?
• Are all proxy accounts nonprivileged?
• Do you log operators' HSC activities on a hardcopy printer?
• Does the HSC console have a sign-in log, and are your operators trained to use it?
• Did you ensure that users are familiar with the restrictions on the use of access control strings in the evaluated configuration?

Managing the Audit Reporting System

• Are the audit server and OPCOM processes running?
• Do you have one audit log file for the entire cluster?
• Are you using a hardcopy terminal as the security operator terminal?
• Is the security operator terminal accessible only to authorized personnel?
• Do you have a procedure for reviewing the audit log file on a regular basis?
• Does the audit log file have both Audit and Alarm ACEs?
• Are the Authorization and ACL event classes enabled?
• Did you put Audit ACEs on all captive login command procedures and their home directories?

Reusing Disks, Tapes, and Terminals

• Is high-water marking enabled on system disk volumes?
• Are users trained to shut off their terminals after logging out?
• Do you have a procedure for erasing tapes before they are used again?

Building a Single Security Domain

• Does your cluster have only one copy of the following files?

  NETOBJECT.DAT	NET$PROXY.DAT
  NETPROXY.DAT	QMAN$MASTER.DAT
  RIGHTSLIST.DAT	SYS$QUEUE_MANAGER.QMAN$QUEUES
  SYSUAF.DAT	SYSUAFALT.DAT
  VMS$AUDIT_SERVER.DAT	VMSMAIL_PROFILE.DATA
  VMS$OBJECTS.DAT	VMS$PASSWORD_DICTIONARY.DATA
  VMS$PASSWORD_HISTORY.DATA	VMS$PASSWORD_POLICY.EXE

• Are all nodes in the cluster part of the C2 configuration?

Starting the System

• Did you set security-sensitive parameters to the following values?

  LGI_CALLOUTS	0
  LOAD_PWD_POLICY	0
  MAXSYSGROUP	7
  NISCS_CONV_BOOT	0
  RMS_FILEPROT	65,280
  SECURITY_POLICY	0
  STARTUP_P1	" "

• Is the CONNECT CONSOLE command disabled? (On VAX 9000 systems, is the SET SPU_UPDATE_OFF command in effect?)
• Have you excluded FYDRIVER from your system?

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