Monitor Active Directory

The Active Directory (AD) database (also known as the NT Directory Service (NTDS) database) is the central repository for user, computer, network, device and security objects in an AD domain or forest. You can use Splunk Enterprise to record changes to AD, such as the addition or removal of a user, host, or domain controller (DC). If you have Splunk Cloud, you must use the Splunk Universal forwarder to collect Active Directory data.

You can configure AD monitoring to watch for changes to your Active Directory forest and collect user and machine metadata. You can use this feature combined with dynamic list lookups to decorate or modify events with any information available in AD.

After you have configured Splunk Enterprise to monitor your Active Directory, it takes a baseline snapshot of the AD schema. It uses this snapshot to establish a starting point for monitoring.

The AD monitoring input runs as a separate process called splunk-admon.exe. It runs once for every Active Directory monitoring input you define in Splunk Enterprise.

Why monitor Active Directory?

If you maintain the integrity, security, and health of your Active Directory, then what happens with it day to day is a concern. Splunk Enterprise lets you monitor what and when things changed in your AD, and who changed them.

You can transform this data into reports for corporate security compliance or forensics, for example. You can also use the data retrieved for intrusion alerts for immediate response. Additionally, you can create health reports with the data indexed for future AD infrastructure planning activities, such as assignment of operations master roles, AD replicas, and global catalogs across DCs.

What do you need to monitor Active Directory?

The following table lists the permissions you must have to monitor an Active Directory schema.

Activity	Required permissions
Monitor an Active Directory schema	* Splunk Enterprise must run on Windows * Splunk Enterprise must run as a domain user * The user Splunk Enterprise runs as must have read access to all AD objects that you want to monitor

Technical considerations for monitoring Active Directory

For best results with monitoring AD, read and understand the following:

• The AD monitor is only available on Splunk Enterprise on Windows.
• While you cannot monitor AD changes from a *nix version of Splunk Enterprise, you can forward AD data from a Windows version of Splunk Enterprise to a *nix indexer.
• The AD monitoring process can run under a full instance or on any kind of forwarder.
• The host that monitors changes to AD must belong to the domain or forest you want to monitor.
• The user that Splunk Enterprise runs as must also be part of the domain.
• The permissions that the user has determine which parts of AD Splunk can monitor.

For information on deciding which user Splunk should run as at installation time, see Choose the user Splunk should run as in the Installation Manual.

How the AD monitor interacts with AD

When you set up an AD monitoring input, the input connects to an AD domain controller to authenticate and, if necessary, perform any security ID (SID) translations while it gathers the AD schema or change events.

The AD monitor uses the following logic to interact with Active Directory after you set it up:

1. If you specify a domain controller when you define the input (either with the targetDc setting in inputs.conf or the "Target domain controller" field in Splunk Web, then the input uses that domain controller for AD operations.
2. If you do not specify a domain controller, then the input does the following:
   1. The input attempts to use the local system cache to authenticate or resolve SIDs.
   2. If the monitor cannot authenticate or resolve SIDs that way, it attempts a connection to the domain controller that the machine that runs the input used to log on.
   3. If that does not work, then the input attempts to use the closest AD domain controller that has a copy of the Global Catalog.
3. If the domain controller that you specify is not valid, or a domain controller cannot be found, then the input generates an error message.

The AD monitor does not chase LDAP referrals

If the AD monitor makes an LDAP query and receives a referral, it does not chase this referral to complete the query. An LDAP referral represents a problem with your LDAP configuration and you or your designated administrators should determine and fix the configuration problem within AD.

Configure Active Directory monitoring

You can configure AD monitoring either in Splunk Web or by editing configuration files. More options, such as the ability to configure monitors for multiple DCs, are available when using configuration files.

Go to the Add New page

You can get there by two routes.

• Splunk Home
• Splunk Settings

By Splunk Settings:

1. Click Settings in the upper right corner of Splunk Web.
2. Click Data Inputs.
3. Click Active Directory monitoring.
4. Click New to add an input.

By Splunk Home:

1. Click the Add Data link in Splunk Home.
2. Click Monitor to monitor Active Directory on the local Windows machine.

Select the input source

1. In the left pane, select Active Directory monitoring.
2. In the Collection name field, type in a unique name for the input that you will remember.
3. (Optional) In the Target domain controller field, enter the host name or IP address of the domain controller you want to use to monitor AD.
4. (Optional) In the Starting node field, type in the Active Directory node you want the input to begin monitoring from. Use the Lightweight Directory Access Protocol (LDAP) format, for example, DC=Splunk-Docs,DC=com.
5. (Optional) You can click the Browse button to browse through a list of available Active Directory nodes to browse through a list of available AD domains.
6. Check Monitor Subtree if you want the input to monitor all sub-nodes of the node you entered in the "Starting node" field.
7. Click Next.

Specify input settings

The Input Settings page lets you specify application context, default host value, and index. All of these parameters are optional.

Note: Host only sets the host field in the resulting events. It does not tell the input to look on a specific host on your network.

1. Select the appropriate Application context for this input.
2. Set the Host name value. You have several choices for this setting. Learn more about setting the host value in "About hosts".
3. Set the Index that Splunk Enterprise should send data to. Leave the value as "default", unless you have defined multiple indexes to handle different types of events. In addition to indexes for user data, Splunk Enterprise has a number of utility indexes, which also appear in this dropdown box.
4. Click Review.

Review your choices

After specifying all your input settings, review your selections. Splunk Enterprise lists all options you selected, including the type of monitor, the source, the source type, the application context, and the index.

1. Review the settings.
2. If they do not match what you want, click < to go back to the previous step in the wizard. Otherwise, click Submit.

Splunk Enterprise then loads the "Success" page and begins indexing the specified Active Directory node.

Configure AD monitoring with configuration files

The inputs.conf configuration file controls Active Directory monitoring configurations. Edit copies of inputs.conf in the %SPLUNK_HOME%\etc\system\local directory. If you edit them in the default directory, your changes are overwritten when you upgrade. For more information about configuration file precedence, see "Configuration file precedence" in this manual.

1. Open %SPLUNK_HOME%\etc\system\local\inputs.conf for editing. You might need to create this file if it does not exist.
2. Add the appropriate AD monitoring stanzas and settings.

By default, when you enable AD monitoring inputs, Splunk Enterprise gathers AD change data from the first domain controller that it can attach to. If that is acceptable, no further configuration is necessary.

inputs.conf settings

inputs.conf contains one stanza for each AD monitoring input, with a header like the following:

[admon://<name of stanza>]

In each stanza, you can specify:

Attribute	Required?	Description	Default
targetDc	Yes	The unique name of the domain controller you want to use for AD monitoring. Specify a unique name for this attribute if: You have a very large AD and you only want to monitor information in a particular Organizational Unit (OU), subdomain, etc. You have a specific (read-only) domain controller that can be used for monitoring purposes in a high security environment. You have multiple domains or forests in with transitive trusts established, and want to target a different tree than the one where the host that runs Splunk Enterprise resides. You want to configure multiple AD monitoring inputs to target multiple domain controllers. For example, to monitor AD replication across a distributed environment. To target multiple DCs, add another [admon://<uniquename>targetDc] stanza for a target in that tree.	n/a
startingNode	No	A fully qualified Lightweight Directory Access Protocol (LDAP) name (for example: "LDAP://OU=Computers,DC=ad,DC=splunk,DC=com") that specifies where in the AD tree that Splunk Enterprise should begin its indexing. The software starts there and enumerates down to sub-containers, depending on the configuration of the monitorSubtree attribute. The value of startingNode must be within the scope of the DC you are targeting for Splunk Enterprise to get AD data.	The highest root domain in the tree that Splunk Enterprise can access.
monitorSubtree	No	How much of the target AD container to index. A value of 0 means to index only the target container, and not traverse into subcontainers within that container. A value of 1 means to enumerate all sub-containers and domains that it has access to.	1 (monitor all domains that Splunk Enterprise has access to)
baseline	No	Whether or not the input enumerates all existing available AD objects when it first runs. A value of 0 means not to set a baseline. A value of 1 means to set a baseline.	1 (set the baseline.)
index	No	The index to route AD monitoring data to.	the 'default' index.
disabled	No	Whether or not the Splunk should run the input. A value of 0 means that the input is enabled, and a value of 1 means that the input is disabled.	0 (enabled).

Example AD monitoring configurations

The following are examples of how to use inputs.conf to monitor desired portions of your AD network.

To index data from the top of the AD directory:

#Gather all AD data that this server can see

[admon://NearestDC]
targetDc =
startingNode =

To use a DC that is at a higher root level than an OU you want to target for monitoring:

# Use the pri01.eng.ad.splunk.com domain controller to get all AD metadata for
# the Computers OU in this forest. We want schema data for the entire AD tree, not
# just this node.

[admon://DefaultTargetDc]
targetDc = pri01.eng.ad.splunk.com
startingNode = OU=Computers,DC=eng,DC=ad,DC=splunk,DC=com

To monitor multiple domain controllers:

# Get change data from two domain controllers (pri01 and pri02) in the same AD tree.
# Index both and compare/contrast to ensure AD replication is occurring properly.

[admon://DefaultTargetDc]
targetDc = pri01.eng.ad.splunk.com
startingNode = OU=Computers,DC=eng,DC=ad,DC=splunk,DC=com

[admon://SecondTargetDc]
targetDc = pri02.eng.ad.splunk.com
startingNode = OU=Computers,DC=eng,DC=ad,DC=splunk,DC=com

Sample AD monitoring output

When the Splunk AD monitoring utility runs, it gathers AD change events, which are then indexed by Splunk software. To view these events as they arrive, use the Search app.

There are several types of AD change events that Splunk software can index. Examples of these events follow. Some of the content of these events has been obscured or altered for publication purposes.

Update event

When an AD object changes, Splunk generates an update event. The software logs this change as type admonEventType=Update.

           
2/1/10
3:17:18.009 PM                 
                
02/01/2010 15:17:18.0099
dcName=stuff.splunk.com
admonEventType=Update
Names:
                objectCategory=CN=Computer,CN=Schema,CN=Configuration
                name=stuff2
                displayName=stuff2
                distinguishedName=CN=stuff2,CN=Computers
Object Details:
                sAMAccountType=805306369
                sAMAccountName=stuff2
                logonCount=4216
                accountExpires=9223372036854775807
                objectSid=S-1-5-21-3436176729-1841096389-3700143990-1190
                primaryGroupID=515
                pwdLastSet=06:30:13 pm, Sat 11/27/2010
                lastLogon=06:19:43 am, Sun 11/28/2010
                lastLogoff=0
                badPasswordTime=0
                countryCode=0
                codePage=0
                badPwdCount=0
                userAccountControl=4096
                objectGUID=blah
                whenChanged=01:02.11 am, Thu 01/28/2010
                whenCreated=05:29.50 pm, Tue 11/25/2008
                objectClass=top|person|organizationalPerson|user|computer
Event Details:
                uSNChanged=2921916
                uSNCreated=1679623
                instanceType=4
Additional Details:
                isCriticalSystemObject=FALSE
                servicePrincipalName=TERMSRV/stuff2|TERMSRV blah
                dNSHostName=stuff2.splunk.com
                operatingSystemServicePack=Service Pack 2
                operatingSystemVersion=6.0 (6002)
                operatingSystem=Windows Vista? Ultimate
localPolicyFlags=0
 

Delete event

When an AD object has been marked for deletion, Splunk software generates a delete event. The event type is similar to admonEventType=Update, except that it contains the isDeleted=True key/value pair at the end of the event.

2/1/10
3:11:16.095 PM                 
 
02/01/2010 15:11:16.0954
dcName=stuff.splunk.com
admonEventType=Update
Names:
                name=SplunkTest
DEL:blah
                distinguishedName=OU=SplunkTest\0ADEL:blah,CN=Deleted Objects
DEL:blah
Object Details:
                objectGUID=blah
                whenChanged=11:31.13 pm, Thu 01/28/2010
                whenCreated=11:27.12 pm, Thu 01/28/2010
                objectClass=top|organizationalUnit
Event Details:
                uSNChanged=2922895
                uSNCreated=2922846
                instanceType=4
Additional Details:
                dSCorePropagationData=20100128233113.0Z|20100128233113.0Z|20100128233113.0Z|16010108151056.0Z
                lastKnownParent=stuff
                '''isDeleted=TRUE'''
 

Sync event

When AD monitoring inputs are configured, Splunk software tries to capture a baseline of AD metadata when it starts. Splunk software generates event type admonEventType=Sync, which represents the instance of one AD object and all its field values. Splunk software tries to capture all of the objects from the last recorded Update Sequence Number (USN).

When you restart Splunk Enterprise or the splunk-admon.exe process, the software logs an extra 'sync' event. This is normal.

2/1/10
3:11:09.074 PM                 
 
02/01/2010 15:11:09.0748
dcName=ftw.ad.splunk.com
admonEventType=Sync
Names:
                name=NTDS Settings
                distinguishedName=CN=NTDS Settings,CN=stuff,CN=Servers,CN=Default-First-Site-Name,CN=Sites,CN=Configuration
                cn=NTDS Settings
                objectCategory=CN=NTDS-DSA,CN=Schema,CN=Configuration,DC=ad,DC=splunk,DC=com
                fullPath=LDAP://stuff.splunk.com/<GUID=bla bla bla>
                CN=NTDS Settings
Object Details:
                whenCreated=10:15.04 pm, Tue 02/12/2008
                whenChanged=10:23.00 pm, Tue 02/12/2008
                objectGUID=bla bla bla
                objectClass=top|applicationSettings|nTDSDSA
                classPath=nTDSDSA
Event Details:
                instanceType=4
Additional Details:
                systemFlags=33554432
                showInAdvancedViewOnly=TRUE
                serverReferenceBL=CN=stuff,CN=Domain System Volume (SYSVOL share),CN=File Replication Service,CN=System
                options=1
                msDS-hasMasterNCs=DC=ForestDnsZones|DC=DomainDnsZones|CN=Schema,CN=Configuration|CN=Configuration
                msDS-HasInstantiatedNCs=
                msDS-HasDomainNCs=blah
                msDS-Behavior-Version=2
                invocationId=bla bla bla
                hasMasterNCs=CN=Schema,CN=Configuration|CN=Configuration
                dSCorePropagationData=
                dMDLocation=CN=Schema,CN=Configuration
                nTSecurityDescriptor=NT AUTHORITY\Authenticated Users
SchemaName=LDAP://stuff.splunk.com/schema/nTDSDSA                          

Schema event

When you restart Splunk Enterprise after configuring it for AD monitoring, it generates a schema type event: admonEventType=schema. This event shows the definitions of every object in the Active Directory structure. The available, required and optional fields are listed for each AD object. Failure to see all of these fields can indicate a problem with Active Directory.

02/01/2010 15:11:16.0518
dcName=LDAP://stuff.splunk.com/
admonEventType=schema
className=msExchProtocolCfgSMTPIPAddress
classCN=ms-Exch-Protocol-Cfg-SMTP-IP-Address
instanceType=MandatoryProperties
nTSecurityDescriptor=MandatoryProperties
objectCategory=MandatoryProperties
objectClass=MandatoryProperties
adminDescription=OptionalProperties
adminDisplayName=OptionalProperties
allowedAttributes=OptionalProperties
allowedAttributesEffective=OptionalProperties
allowedChildClasses=OptionalProperties
allowedChildClassesEffective=OptionalProperties
bridgeheadServerListBL=OptionalProperties
canonicalName=OptionalProperties
cn=OptionalProperties
createTimeStamp=OptionalProperties
description=OptionalProperties
directReports=OptionalProperties
displayName=OptionalProperties
displayNamePrintable=OptionalProperties
distinguishedName=OptionalProperties
dSASignature=OptionalProperties
dSCorePropagationData=OptionalProperties
extensionName=OptionalProperties
flags=OptionalProperties
fromEntry=OptionalProperties
frsComputerReferenceBL=OptionalProperties
fRSMemberReferenceBL=OptionalProperties
fSMORoleOwner=OptionalProperties
heuristics=OptionalProperties
isCriticalSystemObject=OptionalProperties
isDeleted=OptionalProperties
isPrivilegeHolder=OptionalProperties
lastKnownParent=OptionalProperties
legacyExchangeDN=OptionalProperties
managedObjects=OptionalProperties
masteredBy=OptionalProperties
memberOf=OptionalProperties
modifyTimeStamp=OptionalProperties
mS-DS-ConsistencyChildCount=OptionalProperties
mS-DS-ConsistencyGuid=OptionalProperties
msCOM-PartitionSetLink=OptionalProperties
msCOM-UserLink=OptionalProperties
msDFSR-ComputerReferenceBL=OptionalProperties
msDFSR-MemberReferenceBL=OptionalProperties
msDS-Approx-Immed-Subordinates=OptionalProperties
msDs-masteredBy=OptionalProperties
msDS-MembersForAzRoleBL=OptionalProperties
msDS-NCReplCursors=OptionalProperties
msDS-NCReplInboundNeighbors=OptionalProperties
msDS-NCReplOutboundNeighbors=OptionalProperties
msDS-NonMembersBL=OptionalProperties
msDS-ObjectReferenceBL=OptionalProperties
msDS-OperationsForAzRoleBL=OptionalProperties
msDS-OperationsForAzTaskBL=OptionalProperties
msDS-ReplAttributeMetaData=OptionalProperties
msDS-ReplValueMetaData=OptionalProperties
msDS-TasksForAzRoleBL=OptionalProperties
msDS-TasksForAzTaskBL=OptionalProperties
msExchADCGlobalNames=OptionalProperties
msExchALObjectVersion=OptionalProperties
msExchHideFromAddressLists=OptionalProperties
msExchInconsistentState=OptionalProperties
msExchIPAddress=OptionalProperties
msExchTurfList=OptionalProperties
msExchUnmergedAttsPt=OptionalProperties
msExchVersion=OptionalProperties
msSFU30PosixMemberOf=OptionalProperties
name=OptionalProperties
netbootSCPBL=OptionalProperties
nonSecurityMemberBL=OptionalProperties
objectGUID=OptionalProperties
objectVersion=OptionalProperties
otherWellKnownObjects=OptionalProperties
ownerBL=OptionalProperties
partialAttributeDeletionList=OptionalProperties
partialAttributeSet=OptionalProperties
possibleInferiors=OptionalProperties
proxiedObjectName=OptionalProperties
proxyAddresses=OptionalProperties
queryPolicyBL=OptionalProperties
replicatedObjectVersion=OptionalProperties
replicationSignature=OptionalProperties
replPropertyMetaData=OptionalProperties
replUpToDateVector=OptionalProperties
repsFrom=OptionalProperties
repsTo=OptionalProperties
revision=OptionalProperties
sDRightsEffective=OptionalProperties
serverReferenceBL=OptionalProperties
showInAddressBook=OptionalProperties
showInAdvancedViewOnly=OptionalProperties
siteObjectBL=OptionalProperties
structuralObjectClass=OptionalProperties
subRefs=OptionalProperties
subSchemaSubEntry=OptionalProperties
systemFlags=OptionalProperties
unmergedAtts=OptionalProperties
url=OptionalProperties
uSNChanged=OptionalProperties
uSNCreated=OptionalProperties
uSNDSALastObjRemoved=OptionalProperties
USNIntersite=OptionalProperties
uSNLastObjRem=OptionalProperties
uSNSource=OptionalProperties
wbemPath=OptionalProperties
wellKnownObjects=OptionalProperties
whenChanged=OptionalProperties
whenCreated=OptionalProperties
wWWHomePage=OptionalProperties