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OpenVMS Guide to System Security
12.3.2.2 Removing Proxy Access
Remove proxy access to the system when it is no longer needed. Invoke
AUTHORIZE, and enter the following command to remove proxy access:
UAF> REMOVE/PROXY BOSTON::MARTIN
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12.3.2.3 Procedure for Creating a Proxy Account
When you want to set up a proxy account on your node for use by one or
more users at other nodes, you must perform the following steps. Refer
to the security guidelines listed in Section 12.3.1 as you create the
account.
- Define the purpose of the account, its name, and which network
users will be admitted.
- Create the local account, if necessary, with AUTHORIZE; if the
account already exists, make sure it is restricted and defined as
/NOINTERACTIVE, /NOBATCH, /NETWORK.
- Review the privileges on the account. Generally avoid granting
privileges to proxy login accounts.
- Create the network proxy authorization file, if necessary, with the
AUTHORIZE command CREATE/PROXY. (The system usually creates it
automatically.)
- Allow as many remote users as necessary access to the proxy account
with the AUTHORIZE command ADD/PROXY.
- Check the default protection on the directory, and customize it as
necessary.
- Examine any login command procedure specified by the /LGICMD
qualifier to the ADD command. In captive accounts, make certain that
the login command procedure follows the recommendations in
Section 7.2.4.2. It should reside in a well-protected directory owned by
a user other than the owner of the proxy account. It should prohibit
write access for those who use the account.
- Notify the security administrator at the remote node about which
users from that node have been authorized for access to your node.
12.3.3 Example of a Proxy Account
In Example 12-1, the security administrator at the node WALNUT wants
to create a general access account called GENACCESS. At the same time
the administrator wants to take steps to allow proxy logins by three
users from the node BIRCH: KMahogany, PSumac, and WPine, as well as two
users from the node WILLOW: RDogwood and WCherry. No network proxy
authorization file currently exists.
Example 12-1 Sample Proxy Account |
$ SET DEFAULT SYS$SYSTEM
$ RUN AUTHORIZE
UAF> ADD GENACCESS /PASSWORD=WHYNADGUM/UIC=[236,043] -
_UAF> /DEVICE=STAFFDEV/DIRECTORY=[GENACCESS] -
_UAF> /OWNER="Security Mgmt"/ACCOUNT=SEC -
_UAF> /FLAGS=(DISWELCOME,DISNEWMAIL,GENPWD,DISMAIL) -
_UAF> /NOBATCH/NOINTERACTIVE/MAXDETACH=8 -
_UAF> /LGICMD=LOGIN/MAXACCTJOBS=10
%UAF-I-ADDMSG, user record successfully added
%UAF-I-RDBADDMSGU, identifier GENACCESS value [000236,000043]
added to rights database
%UAF-I-RDBADDMSGU, identifier SEC value [000236,177777] added to
rights database
UAF> CREATE/PROXY
UAF> ADD/PROXY BIRCH::KMAHOGANY GENACCESS/DEFAULT
%UAF-I-NAFADDMSG, proxy from OMNI:.BOSTON.BIRCH::KMAHOGANY to
GENACCESS added
UAF> ADD/PROXY BIRCH::PSUMAC GENACCESS/DEFAULT
%UAF-I-NAFADDMSG, proxy from OMNI:.BOSTON.BIRCH::PSUMAC to
GENACCESS added
UAF> ADD/PROXY BIRCH::WPINE GENACCESS/DEFAULT
%UAF-I-NAFADDMSG, proxy from OMNI:.BOSTON.BIRCH::WPINE to
GENACCESS added
UAF> ADD/PROXY WILLOW::RDOGWOOD GENACCESS/DEFAULT
%UAF-I-NAFADDMSG, proxy from OMNI:.BOSTON.WILLOW::RDOGWOOD to
GENACCESS added
UAF> ADD/PROXY WILLOW::WCHERRY GENACCESS/DEFAULT
%UAF-I-NAFADDMSG, proxy from OMNI:.BOSTON.WILLOW::WCHERRY to
GENACCESS added
UAF> SHOW/PROXY *::*
Default proxies are flagged with a (D)
OMNI:.BOSTON.BIRCH::KMAHOGANY
GENACCESS (D)
OMNI:.BOSTON.BIRCH ::PSUMAC
GENACCESS (D)
OMNI:.BOSTON.BIRCH ::WPINE
GENACCESS (D)
OMNI:.BOSTON.WILLOW ::RDOGWOOD
GENACCESS (D)
OMNI:.BOSTON.WILLOW ::WCHERRY
GENACCESS (D)
UAF> EXIT
{messages}
$ DIRECTORY/SECURITY SYS$STAFF:[000000]GENACCESS.DIR
.
.
.
$ DIRECTORY/SECURITY SYS$STAFF:[GENACCESS]LOGIN.COM
.
.
.
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12.4 Using DECnet Application (Object) Accounts
Network objects are system programs and user-written applications that
permit communication among nodes in a DECnet network. You need to
identify the set of network objects allowed access to your system, and
set up the appropriate access controls for each object. The following
mechanisms are available:
- DECnet object accounts These are individual accounts for specific
network objects (for example, MAIL) automatically configured on your
system. These provide more accountability of remote access to an object
than the default DECnet account provides. (For example, an object can
have a captive account with a login command procedure that grants or
denies access to the object based on the remote node name or user name.)
- Default DECnet account This type of account allows all network
objects general access to the system. It is appropriate for systems
with low security requirements (for example, a local area network of
systems located within a site with no outside connections or dialup
lines). The default DECnet user name lets users perform certain network
operations, such as the exchange of electronic mail between users on
different nodes, without having to supply a user name and password. The
default DECnet user name is also used for file operations when access
control information is not supplied. For example, it lets remote users
access local files on which the file protection has been set to allow
world access. If you do not want remote users accessing
your node, do not create a default DECnet user name. See Section 12.4.3
for information about removing default DECnet accounts.
12.4.1 Summary of Network Objects
You should understand the function of the network objects supplied with
the OpenVMS operating system before you determine the access control to
apply to them. This section provides a description of the most common
network objects.
FAL
The file access listener (FAL) is the remote file access facility. FAL
is an image that receives and processes remote file access requests for
files at the local node.
Use of general FAL access is strongly discouraged.
Open access allows general network access to any files marked
world-accessible. It also allows remote users to create files in any
directory with world write access.
Sites with high security requirements, or sites where it is difficult
to recognize all the intended users, should not create a FAL account.
To control which users gain access, these sites may establish one or
more proxy accounts for specific purposes (see Section 12.3).
MAIL
MAIL is an image that provides personal mail services for OpenVMS
systems. In most cases, allow the MAIL object general access to the
system.
MIRROR
MIRROR is an image used for particular forms of loopback testing. For
example, MIRROR is run during the DECnet phase of the UETP test package.
MOM
MOM is the Maintenance Operations Module. The MOM image downline loads
unattended systems, transferring a copy of an operating system file
image from an OpenVMS node to a target node. The MOM object is
established during a system installation.
NML
NML is the network management listener. Remote users with access to NML
can use NCP TELL commands to gather and report network information from
your DECnet databases.
PHONE
PHONE is an image that allows online conversations with users on remote
OpenVMS systems. Note that if you allow default DECnet access to PHONE,
anyone in the network can get a list of users currently logged in to
the local system and attempt a login using the list of user names.
TASK
Through the default DECnet account, the TASK object allows arbitrary
command procedures (including those that might be used in intrusions)
to be executed on your system.
Note that if you do not allow default DECnet access on your system or
if you disable default DECnet access to the TASK object, you can allow
remote user-written command procedures (tasks) to run on your system
through the use of access control strings or proxy access.
VPM
VPM is the Virtual Performance Monitor Server. Access to VPM is
required to use the cluster monitoring features of the Monitor utility
(MONITOR).
12.4.2 Configuring Network Objects Manually
The command procedure NETCONFIG.COM configures the network objects on
your system automatically, and the command procedure
NETCONFIG_UPDATE.COM updates the network objects automatically.
If you choose not to use the command procedures, you can perform the
following steps to allow network access to specific objects:
- Create a top-level directory for each network object, and specify a
unique owner UIC and group UIC. For example, the following command
sequence creates a top-level directory for the MAIL object on the
system disk:
$ SET DEFAULT SYS$SPECIFIC:[000000]
$ CREATE/DIRECTORY [MAIL$SERVER]/OWNER_UIC=[376,374]
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Table 12-2 lists the directory names, user names, and UICs used
by the NETCONFIG.COM and NETCONFIG_UPDATE.COM command procedures to
create accounts for specific network accounts. For consistency, you
should specify the same information when manually creating network
object accounts. Note that the MOM object is created by the
operating system during installation.
- Using AUTHORIZE, create an account for the object, and use a
generated password. (Note that the user name and password that you
specify must match the password defined for the object in the network
database [described in step 3].)
For example, the following command sequence sets up an account for
the MAIL object:
$ RUN SYS$SYSTEM:AUTHORIZE
UAF> ADD MAIL$SERVER/OWNER=MAIL$SERVER DEFAULT -
_UAF> /PASSWORD=MDU1294B/UIC=[376,374]/ACCOUNT=DECNET -
_UAF> /DEVICE=SYS$SPECIFIC: /DIRECTORY=[MAIL$SERVER] -
_UAF> /PRIVILEGE=(TMPMBX,NETMBX) /DEFPRIVILEGE=(TMPMBX,NETMBX) -
_UAF> /FLAGS=(RESTRICTED,NODISUSER,NOCAPTIVE) /LGICMD=NL: -
_UAF> /NOBATCH /NOINTERACTIVE
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The AUTHORIZE command SHOW MAIL$SERVER displays the network account
set up for the MAIL object, as shown in Example 12-2.
- Use the NCP DEFINE command to associate the user name and password
of the account with the specified object in the network database, as
follows:
$ RUN SYS$SYSTEM:NCP
NCP> DEFINE OBJECT MAIL USER MAIL$SERVER PASSWORD MDU1294B
NCP> EXIT
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- Repeat steps 1 through 3 for each network object.
- When finished, remove default DECnet access from the executor
database, and remove the default DECnet account from the SYSUAF (see
Section 12.4.3).
- Finally, reboot the system to copy changes made to the permanent
executor and object databases to the running system.
Table 12-2 lists the network object defaults.
Table 12-2 Network Object Defaults
Object Name |
Directory and User (Account) Name |
UIC |
FAL
|
FAL$SERVER
|
[376,373]
|
MAIL
|
MAIL$SERVER
|
[376,374]
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MIRROR
|
MIRRO$SERVER
1
|
[376,367]
|
$MOM
|
VMS$COMMON:[MOM$SYSTEM]
2
|
[376,375]
|
NML
|
NML$SERVER
|
[376,371]
|
PHONE
|
PHONE$SERVER
|
[376,372]
|
VPM
|
VPM$SERVER
|
[376,370]
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1Because AUTHORIZE enforces a user name limit of 12
characters, you must truncate the user name (and directory name) of the
MIRROR object account to MIRRO$SERVER.
2MOM has no associated user name.
Example 12-2 UAF Record for MAIL$SERVER
Account |
Username: MAIL$SERVER Owner: MAIL$SERVER
Account: MAIL$SERVER DEFAULT UIC: [376,374] ([DECNET,MAIL$SERVER])
CLI: DCL Tables:
Default: SYS$SPECIFIC:[MAIL$SERVER]
LGICMD:
Login Flags: Restricted
Primary days: Mon Tue Wed Thu Fri Sat Sun
Secondary days:
Primary 000000000011111111112222 Secondary 000000000011111111112222
Day Hours 012345678901234567890123 Day Hours 012345678901234567890123
Network: ##### Full access ###### ##### Full access ######
Batch: ----- No access ------ ----- No access ------
Local: ----- No access ------ ----- No access ------
Dialup: ----- No access ------ ----- No access ------
Remote: ----- No access ------ ----- No access ------
Expiration: (none) Pwdminimum: 6 Login Fails: 0
Pwdlifetime: (none) Pwdchange: (none)
Last Login: (none) (interactive), (none) (non-interactive)
Maxjobs: 0 Fillm: 16 Bytlm: 12480
Maxacctjobs: 0 Shrfillm: 0 Pbytlm: 0
Maxdetach: 0 BIOlm: 12 JTquota: 1024
Prclm: 0 DIOlm: 6 WSdef: 180
Prio: 4 ASTlm: 16 WSquo: 200
Queprio: 0 TQElm: 10 WSextent: 0
CPU: (none) Enqlm: 20 Pgflquo: 25600
Authorized Privileges:
TMPMBX NETMBX
Default Privileges:
TMPMBX NETMBX
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12.4.3 Removing Default DECnet Access to the System
The default DECnet account is appropriate for systems with low security
requirements (see Section 12.4). If your site has moderate or high
security requirements, you should remove default DECnet access to the
system once you have set up accounts for individual network objects.
Caution
Before deleting your default DECNET account, as described in this
section, use the NCP command SHOW KNOWN OBJECTS and the Authorize
utility (AUTHORIZE) to verify that all network objects and layered
products that use network objects have network accounts set up in the
system user authorization file (SYSUAF.DAT). Otherwise, network objects
and layered products that use network objects may not work as expected.
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To do this, remove access to the DECNET account in the network
configuration database, and delete the DECNET account from the SYSUAF.
Removing Default DECnet Access
Execute the following NCP commands to remove the default DECnet access
from the network executor database:
NCP> DEFINE EXECUTOR NONPRIVILEGED USER DEFAULT_DECNET
NCP> PURGE EXECUTOR NONPRIVILEGED PASSWORD
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The DEFAULT_DECNET user specified in the first command is a nonexistent
user account that is specified for auditing purposes only. (A network
login failure message is written to the security audit log file each
time access to your system is attempted through the [nonexistent]
DEFAULT_DECNET account.)
Deleting the DECNET Account
Using AUTHORIZE, remove the DECNET account from SYSUAF, as follows:
$ SET DEFAULT SYS$SYSTEM
$ RUN AUTHORIZE
UAF> REMOVE DECNET
UAF> EXIT
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Delete any files in the [DECNET] directory structure.
Modifying the Volatile Configuration Database
To have the change take effect immediately, modify the volatile
database with the following NCP commands:
NCP> SET EXECUTOR NONPRIVILEGED USER DEFAULT_DECNET
NCP> CLEAR EXECUTOR NONPRIVILEGED PASSWORD
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12.4.4 Setting Privilege Requirements for Remote Object Connections
You can select specific privileges to control the use of DECnet objects
that are specified during network configuration. In such instances, it
becomes a privileged operation either to connect to a privileged DECnet
object or use an outgoing DECnet object.
For example, the following command establishes the requirement that
users initiating a DECnet connection to the remote object MAIL must
possess the OPER and SYSNAM privileges:
NCP> DEFINE OBJECT MAIL OUTGOING CONNECT PRIVILEGES OPER,SYSNAM
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This mechanism is a useful way of limiting access to certain DECnet
applications to privileged users or programs. However, in order to be
effective, the privilege requirement must be imposed consistently on
all nodes in the network.
12.5 Specifying Routing Initialization Passwords
Point-to-point connections are connections over synchronous and
asynchronous lines. For point-to-point connections, especially over
dialup lines, you can use routing initialization passwords to verify
that the initiating node is authorized to form a connection with your
node. Each end of a point-to-point circuit can establish a verifier to
transmit to the other node and specify a verifier expected from the
other node. Before the link is established, each node verifies that it
received the expected verifier from the other node.
Passwords are usually optional for point-to-point connections but are
required for dynamic asynchronous connections. To provide for increased
security when a remote node requests a
dynamic asynchronous connection (which is normally maintained only for
the duration of a telephone call), the node requesting the dynamic
connection supplies a password, but the node receiving the login
request is prevented from revealing a password to the requesting node.
The network address, node name, and password of the requesting node has
to match the local system's routing authorization data.
12.5.1 Establishing a Dynamic Asynchronous Connection
A dynamic asynchronous DECnet connection is a temporary connection
between two
nodes, normally over a telephone line through the use of modems. The
line at each end of the connection can be switched from a terminal line
to a dynamic asynchronous DECnet line. Configuration of dynamic
asynchronous lines is performed automatically by DECnet during
establishment of a dynamic connection. A dynamic asynchronous
connection is normally maintained only for the duration of a telephone
call.
Note
A dynamic asynchronous connection to an OpenVMS node can be initiated
from any node that supports the DECnet asynchronous DDCMP protocol.
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On an OpenVMS node, you can perform steps 1 and 2 of the dynamic
asynchronous connection process before you turn on the network at your
node (step 3). The later steps of the process (starting with step 4)
must occur when the line is being switched to DECnet.
Follow the steps outlined below to establish a dynamic asynchronous
DECnet connection. This procedure assumes the local OpenVMS node is
originating the connection and switching the terminal line on for
DECnet use. The connection must be to an OpenVMS node on which you have
an account with NETMBX privilege. The steps also indicate the actions
that the system manager at the remote OpenVMS node must perform in
order for the dynamic asynchronous DECnet link to be established
successfully.
- Log in to the SYSTEM account and enter the following commands
interactively (or include them in the SYS$MANAGER:SYSTARTUP_VMS.COM
command procedure before you boot the system). These commands load the
asynchronous driver NODRIVER (NOA0) and
install DYNSWITCH software on your system.
$ RUN SYS$SYSTEM:SYSGEN
SYSGEN> CONNECT NOA0/NOADAPTER
SYSGEN> EXIT
$ INSTALL:=$SYS$SYSTEM:INSTALL
$ INSTALL/COMMAND
INSTALL> CREATE SYS$LIBRARY:DYNSWITCH/SHARE -
_ /PROTECT/HEADER/OPEN
INSTALL> EXIT
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The system manager of the remote OpenVMS node must also enter these
commands. Additionally, the system manager at the remote OpenVMS
node must enter the commands given below. These commands enable the use
of virtual terminals for the terminal line that is to be switched, and
set the DISCONNECT characteristic for the terminal line. (The virtual
terminal capability permits the process to continue running if the
physical terminal you are using becomes disconnected.)
$ RUN SYS$SYSTEM:SYSGEN
SYSGEN> CONNECT VTA0/NOADAPTER/DRIVER=TTDRIVER
SYSGEN> EXIT
$ SET TERMINAL/EIGHT_BIT/PERMANENT/MODEM/DIALUP -
_$ /DISCONNECT device-name:
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Device-name is the name of the terminal port to
which the dynamic asynchronous connection is made.
- Establish the required transmit password at the originating end of
the dynamic asynchronous dialup link. The transmit password is the
password sent to the remote node during connection startup. Use NCP to
enter a command to define the transmit password for the remote
node. The password can contain one to eight alphanumeric characters and
should not contain any spaces. Specify the following commands:
$ RUN SYS$SYSTEM:NCP
NCP> DEFINE NODE node-id TRANSMIT PASSWORD password
NCP> EXIT
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Node-id is the name of the remote node with which
your node is forming a connection. In the following example, the
node name of your local node is LOCALA, the transmit password is PASSA,
and the remote node with which you are creating a dynamic asynchronous
dialup link is REMOTC:
$ RUN SYS$SYSTEM:NCP
NCP> DEFINE NODE REMOTC TRANSMIT PASSWORD PASSA
NCP> EXIT
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For each remote node with which you will create a dynamic
asynchronous DECnet dialup link, you must define a transmit password in
a separate command. The system manager for the node at the other
end of the connection must define that same password as a receive
password for your node (the password expected to be received from your
node). The remote system manager should also
specify the parameter INBOUND ROUTER or INBOUND ENDNODE, to indicate
the type of node (router or end node) that is expected to initiate the
dynamic connection.
These are the commands the remote manager should enter:
$ RUN SYS$SYSTEM:NCP
NCP> DEFINE NODE node-id -
_ RECEIVE PASSWORD password INBOUND node-type
NCP> EXIT
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For example, if your node LOCALA is an end node and your transmit
password is PASSA, the manager at REMOTC should issue the following
command:
$ RUN SYS$SYSTEM:NCP
NCP> DEFINE NODE LOCALA RECEIVE PASSWORD PASSA INBOUND ENDNODE
NCP> EXIT
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- Ensure that DECnet is running on both nodes for the remaining
steps. If you have not already done so, turn on the network by entering
the following command (and request that the remote system manager also
do so):
If the network was already running before you began the dynamic
asynchronous connection procedure, enter these commands to cause the
permanent database entry to be entered in the volatile database:
$ RUN SYS$SYSTEM:NCP
NCP> SET NODE node-id ALL
NCP> EXIT
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- The remaining steps can be performed by any OpenVMS user with
NETMBX privilege. Log in to your local OpenVMS system, and enter the
following DCL command on your terminal to cause your process to
function as a terminal emulator (which makes the
remote terminal appear to be a local terminal connection):
SET HOST/DTE device-name:
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Device-name is the name of your local terminal
port that is connected to the modem. If both systems use modems
with autodial capabilities, you can optionally include the /DIAL
qualifier on the SET HOST/DTE command
to cause automatic dialing of the modem on the remote node, as follows:
SET HOST/DTE/DIAL=number device-name:
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- If you are not using automatic dialing, dial in to the remote node
manually.
- Once the dialup connection is made and you receive the remote
OpenVMS system welcome message, log in to your account on the remote
node.
- While logged in to your account on the remote node, enter the
following command
to cause the line to be switched to a DECnet line automatically:
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