Consider the following best practices.
Permissions
Apply the principle of least privilege when configuring permissions for ISA Server administrators, as described in the following section. Carefully determine who is allowed to log on to the ISA Server computer, eliminating access to those who are not critical to the server functions.
Least Privileges
Apply the principle of least privilege, where a user has the minimum privileges necessary to perform a specific task. This helps ensure that if a user account is compromised, the impact is minimized by the limited privileges held by that user.
Keep the Administrators group and other user groups as small as possible. A user who belongs to the Administrators group on the ISA Server computer, for example, can perform any task on the ISA Server computer.
In Standard Edition, users in the Administrators group are implicitly assigned the role of ISA Server Full Administrator. They have full rights to configure and monitor ISA Server.
In Enterprise Edition, users who belong to the Administrators group on the Configuration Storage server can control the enterprise configuration. They can directly modify any data on the Configuration Storage server.
Logging On and Configuring
When you log on to the ISA Server computer, log on with the least privileged account necessary to do the task. For example, to configure a rule, you should log on as an ISA Server administrator. However, if you only want to view a report, log on with lesser privileges.
In general, use an account with restrictive permissions to perform routine tasks that are unrelated to administration, and use an account with broader permissions only when performing specific administrative tasks.
Guest Accounts
We recommend that you do not enable the Guest account on the ISA Server computer.
When a user logs on to the ISA Server computer, the operating system checks whether the credentials match a known user. If the credentials do not match a known user, the user is logged on as Guest, with the same privileges allowed to the Guest account.
ISA Server recognizes the Guest account as the default All Authenticated Users user set.
Discretionary Access Control Lists
With a new installation, ISA Server discretionary access control lists (DACLs) are appropriately configured. In addition, ISA Server reconfigures DACLs when you modify administrative roles and when the Microsoft ISA Server Control service (isactrl) is restarted. For more information, see the section Role-Bas e d Administration Features earlier in this document.
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Because ISA Server periodically reconfigures DACLs, you should not use the Security and Configuration Analysis tool to configure the per-file DACLs on the ISA Server objects. Otherwise, there may be a conflict between the DACLs set by Group Policy and the DACLs that ISA Server tries to configure.
Do not modify the DACLs set by ISA Server. Note that ISA Server does not set DACLs for the objects in the following list. You should set DACLs for the objects in the following list carefully, giving permissions only to trusted, specific users:
Folder for reports (when you select to publish the reports).
Configuration files created when exporting or backing up the configuration.
Log files that are backed up to a different location.
Be sure to carefully set DACLs, giving permissions only to trusted users and groups. Also, be sure to create strict DACLs on objects that are indirectly used by ISA Server. For example, when creating an Open Database Connectivity (ODBC) connection that will be used by ISA Server, be sure to keep the data source name (DSN) secure.
Configure strict DACLs for all applications running on the ISA Server computer. Be sure to configure strict DACLs for associated data in the file system and in the registry.
If you customize the SecurID HTML or error message templates, be sure to configure appropriate DACLs. The recommended DACL is Inherit permission from parent.
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We recommend that you do not save critical data (such as executables and log files) to FAT32 partitions. This is because DACLs cannot be configured for FAT32 partitionsTip
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Revoking User Permissions
When you revoke administrative permissions for an ISA Server administrator, we recommend that you delete the user account from Active Directory® directory service, to ensure that the user no longer has access.
Removing Administrator Permissions
To remove administrator permissions, remove the user from the specific administrator group.
To remove ISA Server administrators who are logged on, from a security group, and add them into a new group, perform the following steps
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Add the administrator account into the new group.
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Log off and then log on with the administrator account, so that the new settings take effect
Remove the administrator account from the original group