- Introduction
- Account Policies
- System Polices and the Policy Editor
- Audit Policy and Auditing Object Access
- The Security Configuration Manager
- Maintaining Trust Relationships
- Apply Your Knowledge
This chapter is from the book
This chapter is from the book
This chapter is from the book
Audit Policy and Auditing Object Access
Implement auditing and monitor security. Implementation includes configuring audit policy, enabling auditing on objects, and analyzing audit logs.
Auditing is the process by which you track access to system resources. The access that you track may be general (such as logging on) or specific (such as access to a specific file or printer), and it may be focused on successful access or unsuccessful access.
Auditing is most often used when you are concerned about unauthorized access to specific system objects (such as files or printers) but also can be used just to track resource usage.
Successful auditing follows a three-step process:
Create the audit policy.
Define the objects to be audited.
Analyze the audit log.
To create the audit policy, you must be an administrator of the server or in the Server Operators group. To define objects to be audited or to analyze the audit log, you must be given the user right Manage Auditing and Security Log; this is configurable from User Manager for Domains.
The Audit Policy
The audit policy defines the kinds of resources you are interested in auditing. This policy does not specifically define what is to be audited; instead it defines what can be audited. In this way, it is very much like placing locks on doors: When a lock is in place, it can either be locked or unlocked, but until you install the locks, you do not have the choice. With audit policy, you define what can be audited, and then, after that, you can define what is to be audited.
The audit policy for a domain (or a standalone server) can be configured to track the success and/or failure of access in a variety of categories. Table 4.1 summarizes the categories.
Table 4.1. Functionality of Various Log Mechanisms
|
Event to Track |
Encompasses |
|
Logon and Logoff |
Tracks logon, logoff, and network connection establishment. |
|
File and Object Access |
Tracks access to system objects such as directories, files, or printers. To track file access, files must be held on an NTFS partition. |
|
LUse of User Rights |
Tracks user-performing tasks that require the use of some right, except where it relates to logon and logoff. For example, the creation of a computer account requires the use of a specific domain right. |
|
User and Group Management |
Tracks the creation, modification, or deletion of us accounts or groups. This includes the modification of user passwords. |
|
Security Policy Changes |
Tracks the modification of user rights, audit policies, or trust relationship policies. |
|
Restart, Shutdown, and System |
Tracks the restart or shutdown of a computer. In addition, this tracks any events that affect system security or the security log. |
|
Process Tracking |
Tracks events such as program activation, handle duplication, indirect object accesses, and program exit. |
Domain audit policy is accessed from the User Manager for Domains. Step by Step 4.6 shows how to configure domain audit policy.
STEP BY STEP
4.6 Configuring Domain Audit Policy
From the Start menu, choose Programs, Administrative Tools (Common), User Manager for Domains.
From the User Manager dialog box, select the Policies menu and choose Audit.
From the Audit Policy dialog box, select the Audit These Events radio button (if it is not already selected).
-
Select the check boxes appropriate for your domain audit policy (see Figure 4.9). Note that you can select either auditing for success, failure, or both for any of the listed event categories. When complete, click OK to finalize the audit policy.
){kind=link}
Figure 4.9. You can choose to audit the success or failure of a variety of events.
Defining Objects to be Audited
For some most event types, auditing is turned on as soon as the audit policy has been defined. However, for objects, such as files, directories, and printers, not only does the audit policy have to be established (File and Object Access), auditing for specific objects also must be enabled. Auditing can be enabled on any printer object. To enable auditing on file or directory objects, however, they must be on NTFS partitions.
For all objects to which auditing can be applied, two properties must be configured for auditing to be successful:
You must define who you are monitoring. (This can be a group as large as Everyone or as small as a specific user.)
You must define the specific actions for which you are watching.
The actions you are watching for will vary depending on the kind of object you are auditing. (For instance, printer actions differ from file actions.) Each object can have its own user list and actions associated with it.
Enabling Auditing of Printers
If you have the user right Manage Auditing and Security Logs, you can configure a printer to be audited. Regardless of the permissions, you have to access that printer (even if you have no access to the printer). For any individual user or group, you can audit a variety of actions. Table 4.2 describes the actions you can audit for printers.
Table 4.2. Printer Auditing Events
|
Event to Track |
Encompasses |
|
|
Tracks the success or failure of printing to this printer. |
|
Full Control |
Tracks the use of the Full Control permission for this printer. |
|
Delete |
Tracks deletion of print jobs in the queue of this printer. |
|
Change Permissions |
Tracks the changing of permissions for this printer. |
|
Take Ownership |
Tracks taking ownership of this printer. |
Step by Step 4.7 describes the process for configuring auditing for a printer. (This assumes that the audit policy has already been put in place to monitor File and Object Access.)
STEP BY STEP
4.7 Configuring Auditing on a Printer
-
From the Start menu, choose Settings, Printers.
-
From the Printers dialog box, right-click the printer you want to audit and from the menu that appears and choose Properties.
-
From the Properties dialog box, select the Security tab and click the Auditing button on that property sheet.
-
From the Printer Auditing dialog box, click the Add button and choose the users and/or groups for which you want to configure auditing.
-
For each user and/or group you selected in step 4, select that entry in the Name field on the Printer Auditing dialog box and then select the events you want to audit (see Figure 4.10).
-
When you have completed the audit configuration, click OK to save it.
){kind=link}
Figure 4.10. Each user or group can be audited for its own specific events.
You can follow Step by Step 4.7 to configure auditing for as many printers as is appropriate in your environment.
Enabling Auditing of Files and Folders
If you have the user right Manage Auditing and Security Logs, you can configure a file or folders, regardless of the permissions you have to access that printer (even if you have no access to the printer). However, the file or folder must be on an NTFS partition to audit it; file and folders on FAT partitions cannot be audited, and they either have to be moved to NTFS partitions or the partition on which they are on must be converted to NTFS. For any individual user or group, you can audit a variety of actions. Table 4.3 describes the actions you can audit for files and folders.
Table 4.3. File and Folder Auditing Events
|
Event to Track |
Encompasses |
|
Traverse Folder/Execute File |
Tracks access of file or folders via the audited folder (for folders) or the execution of a file (for files). |
|
List Folder/Read Data |
Tracks the listing of the contents of a folder (for folders) or the reading of the contents of a file (for files). |
|
Read Attributes |
Tracks the listing of the attributes of a file or a folder. This would include attributes such as read-only or hidden. |
|
Read Extended Attributes |
Tracks the listing of the extended attributes of a file or folder. This would include attributes as defined by specific programs and would vary from program to program. |
|
Create Files/Write Data |
Tracks the creation of files within an audited folder (for folders) or the writing of data (for files). |
|
Create Folders/Append Data |
Tracks the creation of new folders within an audited folder (for folders) or the appending of data to a file (for files). |
|
Write Attributes |
Tracks the modification of the attributes (such as read-only) for a file or folder. |
|
Write Extended Attributes |
Tracks the modification of extended attributes for a file or folder. |
|
Delete Subfolders and Files |
Tracks the deletion of subfolders or files within an audited folder (applies only to folders). |
|
Delete |
Tracks the deletion of the audited file or folder. |
|
Read Permissions |
Tracks the listing of the NTFS permissions on a file or folder. |
|
Change permissions |
Tracks the changing of the NTFS permissions on a file or folder. |
|
Take Ownership |
Tracks the taking of ownership of the audited file or folder. |
|
Synchronize |
Tracks the synchronization of multiple threads waiting for the file or folder. This applies only to multithreaded programs. |
Step by Step 4.8 describes the process for configuring auditing for a file or folder. (This assumes that the audit policy has already been put in place to monitor File and Object Access and that the file or folder is on an NTFS partition.)
STEP BY STEP
4.8 Configuring Auditing on a File or Folder
-
Navigate to the file or folder you want to audit. For example, you may do this in Windows Explorer.
-
Right-click the file or folder you want to audit and from the menu that appears choose Properties.
-
From the Properties dialog box, select the Security tab and click the Advanced button at the bottom of that that property sheet.
-
In the Access Control Setting dialog box, select the Auditing tab and click the Add button on that property sheet, choosing a user or group from the dialog box that appears.
-
On the Audit Entry dialog box, select the scope to which this auditing should apply. (By default, it applies to this object and all objects contained within it, but you can modify that from the Apply Onto pull-down list.)
-
On the Audit Entry dialog box, select the specific events that you want to audit (see Figure 4.11).
-
Click OK after you have configured this audit entry.
-
Repeat steps 4–7 for each user or group you want to audit.
-
If you do not want the audit properties for the parent container of this object to overwrite the changes you have made here, deselect the Allow Inheritable Auditing Entries to Propagate to This Object check box.
-
Click OK to save the auditing configuration for this object.
){kind=link}
Figure 4.11. From the Directory Auditing dialog box, you can configure auditing of success or failure for any user or groups.
After auditing has been configured, you will want to monitor it from time to time.
Monitoring the Security Log for Audit Entries
A part of any good audit is the monitoring of collected information. This information is stored in the security log, which is accessible using the Event Viewer. What you want to monitor in terms of scope of people, objects, and events depends on your needs, but it might take some adjustment as you begin to actually collect data. Generally, one of three problems arise in auditing:
-
You collect too little data.
-
You collect too much data.
-
You collect the wrong data.
In all three of these cases, the solution is generally hit and miss until you have some experience. You might find, for example, that you begin monitoring successful access to a file by the Everyone group. If this file is popular, you will get a tremendous amount of data. It may be that, after a while, you decide it is better to limit the number of people who you are monitoring and to monitor only access failure.
Regardless of how much information you collect, the steps for viewing are always the same. Step by Step 4.9 describes the procedure.
STEP BY STEP
4.9 Observing Collected Auditing Information in a Security Log
-
From the Start menu, choose Programs, Administrative Tools (Common), Event Viewer.
-
From the Event Viewer dialog box, select the Log menu and choose Security.
-
Scroll through the security data. All entries with a key icon beside them indicate successful operations. All entries with a padlock beside them indicate unsuccessful operations (see Figure 4.12). By double-clicking an entry, you can see the information collected for that event.
){kind=link}
Figure 4.12. The failures of logon were caused by incorrect usernames and passwords. The padlock indicates failure, whereas the key indicates success.
The security log itself might need some adjustment over time. If you are collecting a log of audit information, this log can get very large over time. You have the option of configuring the security log to have a maximum size and also to configure the wrapping of the events within the log. As it pertains to wrapping, you can choose to overwrite old entries when the log gets full (oldest entries always overwritten first) or you can overwrite entries that are older than a specific number of days. In addition, you can configure the log to never overwrite old entries; but this means that the log will have to be archived manually. When the log fills up in the last scenario, no new entries are written until the log is archived manually.
To adjust the properties of your security log, follow Step by Step 4.10.
NOTE
Security Logs and High-Security Environments In high-security environments, it is not acceptable to overwrite the security log or to stop logging because the log is full. In these few cases, it is more desirable for the server to crash than for auditing information to be lost. This action is actually configurable. If you set the Registry value HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa\ crashonauditfail to 1, when the security log fills up, the machine will generate a STOP error (blue screen). At that point, only an administrator can log on to archive the security log and restart the machine. Of course, this must be done with caution and, because it involves Registry changes, you might forfeit your right to have Microsoft support problems you get into as a result—that is, you will be on your own! Also note that, because this is a relatively obscure piece of information, you'll not see it on the exam; so tuck it away in case you need it in the field some day.
STEP BY STEP
4.10 Adjusting the Properties of the Security Log
-
From the Start menu, choose Programs, Administrative Tools (Common), Event Viewer.
-
From the Event Viewer dialog box, select the Log menu and choose Log Settings.
-
From the Event Log Settings dialog box, select Security from the Change Settings for pull-down list (see Figure 4.13).
-
Adjust the maximum log size and the event log wrapping action. If you want to reset the options to the default settings, click the Default button.
-
Click the OK button to exit the dialog box.
){kind=link}
Figure 4.13. The Event Log Settings dialog box will enable you to set the maximum size for a log and the action taken when the log gets full.