Splunk® App for PCI Compliance

Installation and Configuration Manual

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Configure correlation searches

A correlation search scans multiple data sources for defined patterns. When the search finds a pattern, it performs an adaptive response action such as creating a notable event.

Correlation searches can search many types of data sources, including events from any security domain (access, identity, endpoint, network), asset lists, identity lists, threat intelligence, and other data in Splunk platform. The searches then aggregate the results of an initial search with functions in SPL, and take action in response to events that match the search conditions with an adaptive response action. Configure correlation searches to update the settings associated with how they run.

Enable correlation searches

Enable correlation searches to start running adaptive response actions and receiving notable events. Splunk App for PCI Compliance installs with all correlation searches disabled so that you can choose the searches that are most relevant to your use cases.

  1. Select Configure > Content Management.
  2. Filter on a type of Correlation Search.
  3. Locate the name of the correlation search you want to enable.
  4. In the Actions column, click Enable to enable the searches that you want to enable.
  5. After you enable correlation searches, click "Back to PCI Compliance" in the menu bar.

For details about the correlation searches shipped with the Splunk App for PCI Compliance, see Search View Matrix in the User Manual.

Change correlation search scheduling

Change the default search type of a correlation search from real-time to scheduled. Splunk App for PCI Compliance uses indexed real-time searches by default.

  1. From the Content Management page, locate the correlation search you want to change.
  2. In the Actions column, click Change to scheduled.

Editing correlation searches

You can make changes to correlation searches to fit your environment. For example, modify the thresholds used in the search, change the response actions that result from a successful correlation, or change how often the search runs. Modifying a correlation search does not affect existing notable events.

  • Click the name of a correlation search on the Content Management page to edit it.

If you modify the start time and end time for the correlation search, use relative time modifiers. See Specify time modifiers in your search in the Splunk Enterprise Search Manual.

Edit the correlation search in guided mode

You can edit some correlation searches in guided mode. Not all correlation searches support guided search editing. If a search appears grayed-out and has the option to Edit search manually or Edit search in guided mode, the search was built in guided mode and can be edited in guided mode. If a search can be edited in the search box and only has the option to Edit search in guided mode, editing the search in guided mode overwrites the existing search.

  1. Click Edit search in guided mode to open the guided search creation wizard.
  2. Review the search elements in the correlation search, making changes if you want.
  3. Save the search.

Throttle the number of response actions generated by a correlation search

Set up throttling to limit the number of response actions generated by a correlation search. When a correlation search matches an event, it triggers a response action.

By default, every result returned by the correlation search generates a response action. Typically, you may only want one alert of a certain type. You can use throttling to prevent a correlation search from creating more than one alert. Some response actions allow you to specify a maximum number of results in addition to throttling. See Set up adaptive response actions in Splunk App for PCI Compliance.

  1. Select Configure > Content Management.
  2. Click the title of the correlation search you want to edit.
  3. Type a Window duration. During this window, any additional event that matches any of the Fields to group by will not create a new alert. After the window ends, the next matching event will create a new alert and apply the throttle conditions again.
  4. Type the Fields to group by to specify which fields to use when matching similar events. If a field listed here matches a generated alert, the correlation search will not create a new alert. You can define multiple fields, and available fields depend on the search fields that the correlation search returns.
  5. Save the correlation search.

Throttling applies to any type of correlation search response action and occurs before notable event suppression.

Allow non-admins to edit correlation searches

If you want non-admins to edit correlation searches, add the edit correlation searches capability to a different role in Splunk App for PCI Compliance.

  1. Select Configure > General > Permissions.
  2. Locate the role that you want to allow to edit correlation searches.
  3. Select the check box for Edit Correlation Searches for that role.
  4. Click Save.

Correlation searches migration to savedsearches.conf

Starting in the Splunk App for PCI Compliance version 3.4.0, correlationsearches.conf is no longer used to define correlation searches. Instead, savedsearches.conf uniquely identifies correlation searches using the action.correlationsearch.enabled=1 parameter. The correlationsearches.conf file is deprecated.

For stability, the Threat - Correlation Searches - Lookup Gen saved search continues to use the contents of both correlationsearches.conf and savedsearches.conf to populate the correlationsearches KV Store collection used by Incident Review.

Changes the Splunk App for PCI Compliance makes at upgrade

When you upgrade to the Splunk App for PCI Compliance version 3.4.0, the Splunk App for PCI Compliance migrates all correlation searches in your environment, including custom correlation searches. The confcheck_es_correlationmigration.py script migrates all entries in correlationsearches.conf into updated entries in savedsearches.conf. The migration can take up to five minutes to complete after the upgrade.

During the upgrade, the Splunk App for PCI Compliance continues to create notable events without interruption.

Changes you have to make after upgrade

After upgrading to the Splunk App for PCI Compliance version 3.4.0, you have to make additional changes.

  • Check for searches that did not migrate successfully and migrate the correlationsearches.conf entries manually using the parameter definitions below.
  • Update searches that call the correlationsearches REST endpoint.
    • For example, a search that displays a list of correlation searches in your environment would change from

      | rest splunk_server=local /services/alerts/correlationsearches | rename eai:acl.app as app, title as csearch_name | table app security_domain csearch_name description

      to

      | rest splunk_server=local count=0 /services/saved/searches | where match('action.correlationsearch.enabled', "1|[Tt]|[Tt][Rr][Uu][Ee]") | rename eai:acl.app as app, title as csearch_name, action.correlationsearch.label as csearch_label, action.notable.param.security_domain as security_domain | table csearch_name, csearch_label, app, security_domain, description

Both the correlationsearches.conf and savedsearches.conf files are used to populate the KV Store collection used by Incident Review. Custom search macros that reference that KV Store collection continue to work as before, but consider updating them anyway.

correlationsearches.conf parameter translation to savedsearches.conf

All correlationsearches.conf parameters now exist in savedsearches.conf and the correlationsearches.conf file has been deprecated. Do not update it directly except to manually migrate correlation search definitions.

Identification parameters for correlation searches

New parameters identify whether a saved search is a correlation search and the name of the correlation search.

correlationsearches.conf parameter
in pre-3.4.0 versions
savedsearches.conf parameter
starting in 3.4.0
Notes
N/A action.correlationsearch=0 This is an internal parameter and can be ignored.
A stanza for the search exists action.correlationsearch.enabled=1 This parameter identifies a saved search as a correlation search.
rule_name action.correlationsearch.label This parameter provides the name of the correlation search.
description description This parameter provides the description of the correlation search.

Notable event parameters for correlation searches

The action.notable parameter identifies a notable event associated with a correlation search. The parameters that describe additional details associated with the notable event now exist in the savedsearches.conf file.

correlationsearches.conf parameter
in pre-3.4.0 versions
savedsearches.conf parameter
starting in 3.4.0
security_domain action.notable.param.security_domain
severity action.notable.param.severity
rule_title action.notable.param.rule_title
rule_description action.notable.param.rule_description
nes_fields action.notable.param.nes_fields
drilldown_name action.notable.param.drilldown_name
drilldown_search action.notable.param.drilldown_search
default_status action.notable.param.default_status
default_owner action.notable.param.default_owner

Related search parameters for correlation searches

Searches related to a correlation search, such as the context-generating searches associated with a correlation search that uses extreme search, are now part of a JSON blob action.correlationsearch.related_searches parameter.

correlationsearches.conf parameter
in pre-3.4.0 versions
savedsearches.conf parameter
starting in 3.4.0
related_search_name = Endpoint - Emails By Source - Context Gen
related_search_name.0 = Endpoint - Emails By Destination Count - Context Gen
action.correlationsearch.related_searches = [\
    "Endpoint - Emails By Source - Context Gen",\
    "Endpoint - Emails By Destination Count - Context Gen"\
]

Example correlation search stanzas from this version and previous versions

The savedsearches.conf stanza for a correlation search looks as follows starting in 3.4.0.

[Access - Concurrent App Accesses - Rule]
action.correlationsearch = 0
action.correlationsearch.enabled = 1
action.correlationsearch.label = Concurrent Login Attempts Detected
action.email.sendresults = 0
action.notable = 0
action.notable.param.security_domain = access
action.notable.param.severity = medium
action.notable.param.rule_title = Concurrent Access Event Detected For $user$
action.notable.param.rule_description = Concurrent access attempts to $app1$ by $user$ from two different sources( $src1$, $src2$ ) have been detected.
action.notable.param.nes_fields = user
action.notable.param.drilldown_name = View access attemps by $user$
action.notable.param.drilldown_search = | datamodel Authentication Authentication search | search Authentication.user="$user$"
action.risk = 1
action.risk.param._risk_object = user
action.risk.param._risk_object_type = user
action.risk.param._risk_score = 20
alert.suppress = 1
alert.suppress.fields = user
alert.suppress.period = 86300s
alert.track = false
cron_schedule = 10 * * * *
description = Alerts on concurrent access attempts to an app from different hosts. These are good indicators of shared passwords and potential misuse.
disabled = True
dispatch.earliest_time = -70m@m
dispatch.latest_time = -5m@m
enableSched = 1
is_visible = false
request.ui_dispatch_app = SplunkEnterpriseSecuritySuite
search = | tstats `summariesonly` count from datamodel=Authentication.Authentication by _time,Authentication.app,Authentication.src,Authentication.user span=1s | `drop_dm_object_name("Authentication")` | eventstats dc(src) as src_count by app,user | search src_count>1 | sort 0 + _time | streamstats current=t window=2 earliest(_time) as previous_time,earliest(src) as previous_src by app,user | where (src!=previous_src) | eval time_diff=abs(_time-previous_time) | where time_diff<300

In previous versions of the Splunk App for PCI Compliance, the savedsearches.conf and correlationsearches.conf definitions for the same correlation search looks as follows. savedsearches.conf

[Access - Concurrent App Accesses - Rule]
action.email.sendresults            = 0
action.risk                         = 1
action.risk.param._risk_object      = user
action.risk.param._risk_object_type = user
action.risk.param._risk_score       = 20
alert.suppress                      = 1
alert.suppress.fields               = user
alert.suppress.period               = 86300s
alert.track                         = false
cron_schedule                       = 10 * * * *
disabled                            = True
dispatch.earliest_time              = -70m@m
dispatch.latest_time                = -5m@m
enableSched                         = 1
is_visible                          = false
request.ui_dispatch_app             = SplunkEnterpriseSecuritySuite
search                              = | tstats `summariesonly` count from datamodel=Authentication.Authentication by _time,Authentication.app,Authentication.src,Authentication.user span=1s | `drop_dm_object_name("Authentication")` | eventstats dc(src) as src_count by app,user | search src_count>1 | sort 0 + _time | streamstats current=t window=2 earliest(_time) as previous_time,earliest(src) as previous_src by app,user | where (src!=previous_src) | eval time_diff=abs(_time-previous_time) | where time_diff<300

correlationsearches.conf

[Access - Concurrent App Accesses - Rule]
security_domain     = access
severity            = medium
rule_name           = Concurrent Login Attempts Detected
description         = Alerts on concurrent access attempts to an app from different hosts. These are good indicators of shared passwords and potential misuse.
rule_title          = Concurrent Access Event Detected For $user$
rule_description    = Concurrent access attempts to $app1$ by $user$ from two different sources( $src1$, $src2$ ) have been detected.
nes_fields          = user
drilldown_name      = View access attemps by $user$
drilldown_search    = | datamodel Authentication Authentication search | search Authentication.user="$user$"
default_owner       =
default_status      =
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This documentation applies to the following versions of Splunk® App for PCI Compliance: 3.4.0, 3.4.1, 3.4.2, 3.5.0, 3.6.0, 3.6.1, 3.7.0, 3.7.1, 3.7.2, 3.8.0, 3.8.1


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