adding new detection. updating message on others

detections/endpoint/windows_admon_default_group_policy_object_modified.yml

@@ -43,7 +43,7 @@ tags:
   kill_chain_phases:
   - Installation
   - Actions on Objectives
-  message: UPDATE message
+  message: A default domain group policy was updated on $dcName$
   mitre_attack_id:
   - T1484
   - T1484.001

detections/endpoint/windows_admon_group_policy_object_created.yml

@@ -43,7 +43,7 @@ tags:
   kill_chain_phases:
   - Installation
   - Actions on Objectives
-  message: UPDATE message
+  message: A new group policy objected was created on $dcName$
   mitre_attack_id:
   - T1484
   - T1484.001

detections/endpoint/windows_default_group_policy_object_modified.yml

@@ -44,7 +44,7 @@ tags:
   kill_chain_phases:
   - Installation
   - Actions on Objectives
-  message: UPDATE message
+  message: A default group policy object was modified on $Computer$ by $SubjectUserSid$
   mitre_attack_id:
   - T1484
   - T1484.001

detections/endpoint/windows_default_group_policy_object_modified_with_gpme.yml

@@ -0,0 +1,82 @@
+name: Windows Default Group Policy Object Modified with GPME
+id: eaf688b3-bb8f-454d-b105-920a862cd8cb
+version: 1
+date: '2023-04-24'
+author: Mauricio Velazco, Splunk
+type: TTP
+datamodel: []
+description: The following analytic leverages the Endpoint datamodel to identify the potential edition of a default Group Policy Object. A fresh installation of an Active Directory network will typically contain
+  two default group policy objects `Default Domain Controllers Policy` and `Default Domain Policy`. The default domain controllers policy is used to enforce and set policies to all the domain controllers within the domain environment.
+  The default domain policy is linked to all users and computers by default. An adversary who has obtained privileged access to an Active Directory network may modify the default group 
+  policy objects to obtain further access, deploy persistence or execute malware across a large number of hosts. Security teams should monitor the edition of the default GPOs.
+search: ' | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime from datamodel=Endpoint.Processes where Processes.process_name=mmc.exe (Processes.process =*gpme.msc*) AND (Processes.process = "*31B2F340-016D-11D2-945F-00C04FB984F9*" OR Processes.process = "*6AC1786C-016F-11D2-945F-00C04fB984F9*"  ) by Processes.dest Processes.user Processes.parent_process_name Processes.process_name Processes.process Processes.process_id Processes.parent_process_id 
+  | `drop_dm_object_name(Processes)` 
+  | `security_content_ctime(firstTime)`
+  | `security_content_ctime(lastTime)`
+  | `windows_default_group_policy_object_modified_with_gpme_filter`'
+how_to_implement: To successfully implement this search you need to be ingesting information on process that include the name of the process responsible for the changes from your endpoints into the `Endpoint` datamodel in the `Processes` node. In addition, confirm the latest CIM App 4.20 or higher is installed and the latest TA for the endpoint product.
+known_false_positives: The default Group Policy Objects within an AD network may be legitimately updated for administrative operations, filter as needed.
+references:
+- https://attack.mitre.org/techniques/T1484/
+- https://attack.mitre.org/techniques/T1484/001
+- https://www.trustedsec.com/blog/weaponizing-group-policy-objects-access/
+- https://adsecurity.org/?p=2716
+- https://learn.microsoft.com/en-us/previous-versions/windows/it-pro/windows-server-2012-r2-and-2012/dn265969(v=ws.11)
+tags:
+  analytic_story:
+  - Active Directory Privilege Escalation
+  - Sneaky Active Directory Persistence Tricks
+  asset_type: Endpoint
+  cis20:
+  - CIS 3
+  - CIS 5
+  - CIS 16
+  confidence: 50
+  context:
+  - Source:Endpoint
+  - Stage:Privilege Escalation
+  - Stage:Persistence
+  dataset:
+  - https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1484.001/default_domain_policy_modified/windows-security.log
+  impact: 100
+  kill_chain_phases:
+  - Installation
+  - Actions on Objectives
+  message: A default group policy object was opened with Group Policy Manage Editor on $dest$
+  mitre_attack_id:
+  - T1484
+  - T1484.001
+  nist:
+  - DE.CM
+  observable:
+  - name: dest
+    type: Hostname
+    role:
+    - Victim
+  - name: parent_process_name
+    type: Process
+    role:
+    - Parent Process
+  - name: process_name
+    type: Process
+    role:
+    - Child Process
+  product:
+  - Splunk Enterprise
+  - Splunk Enterprise Security
+  - Splunk Cloud
+  required_fields:
+  - _time
+  - Processes.dest
+  - Processes.user
+  - Processes.parent_process_name #parent process name
+  - Processes.parent_process #parent cmdline
+  - Processes.original_file_name
+  - Processes.process_name #process name
+  - Processes.process #process cmdline
+  - Processes.process_id
+  - Processes.parent_process_path
+  - Processes.process_path
+  - Processes.parent_process_id
+  risk_score: 50
+  security_domain: endpoint

detections/endpoint/windows_dnsadmins_new_member_added.yml

@@ -39,7 +39,7 @@ tags:
   kill_chain_phases:
   - Installation
   - Actions on Objectives
-  message: UPDATE message
+  message: A new member was added to the DnsAdmins group by $SubjectUserName$
   mitre_attack_id:
   - T1098
   nist:

detections/endpoint/windows_group_policy_object_created.yml

@@ -47,7 +47,7 @@ tags:
   - Exploitation
   - Installation
   - Actions on Objectives
-  message: UPDATE message
+  message: A new group policy objected was created by $User$
   mitre_attack_id:
   - T1484
   - T1484.001

detections/endpoint/windows_large_number_of_computer_service_tickets_requested.yml

@@ -17,7 +17,7 @@ description: The following analytic leverages Event ID 4769, `A Kerberos
   the arbitrary threshold as needed.
 
 search: ' `wineventlog_security` EventCode=4769 ServiceName="*$" TargetUserName!="*$"
-  | bucket span=2m _time 
+  | bucket span=5m _time 
   | stats dc(ServiceName) AS unique_targets values(ServiceName) as host_targets by _time, IpAddress, TargetUserName
   | where unique_targets > 30
   | `windows_large_number_of_computer_service_tickets_requested_filter`'
@@ -48,7 +48,7 @@ tags:
   impact: 60
   kill_chain_phases:
   - Reconnaissance
-  message: UPDATE message
+  message: A large number of kerberos computer service tickets were requested by $IpAddress$ within 5 minutes.
   mitre_attack_id:
   - T1135
   - T1078

detections/endpoint/windows_rapid_authentication_on_multiple_hosts.yml

@@ -42,7 +42,7 @@ tags:
   impact: 60
   kill_chain_phases:
   - Exploitation
-  message: UPDATE message
+  message: The source computer with ip address $IpAddress$ authenticated to a large number of remote endpoints within 5 minutes.
   mitre_attack_id:
   - T1003.002
   nist:

detections/endpoint/windows_special_privileged_logon_on_multiple_hosts.yml

@@ -43,7 +43,7 @@ tags:
   kill_chain_phases:
   - Reconnaissance
   - Exploitation
-  message: UPDATE message
+  message: A source user $Caller_User_Name$ obtained special privileges on a large number of endpoints within 5 minutes.
   mitre_attack_id:
   - T1087
   - T1021.002

tests/endpoint/windows_default_group_policy_object_modified_with_gpme.test.yml

@@ -0,0 +1,13 @@
+name: Windows Default Group Policy Object Modified with GPME Unit Test
+tests:
+- name: Windows Default Group Policy Object Modified with GPME
+  file: endpoint/windows_default_group_policy_object_modified_with_gpme.yml
+  pass_condition: '| stats count | where count > 0'
+  earliest_time: -24h
+  latest_time: now
+  attack_data:
+  - file_name: windows-security.log
+    data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1484.001/default_domain_policy_modified/windows-security.log
+    source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
+    sourcetype: xmlwineventlog
+    update_timestamp: true