From 46bc87e8189b65ca0a476c6d5b48ed180cb101aa Mon Sep 17 00:00:00 2001
From: Steven Dick <38897662+nterl0k@users.noreply.github.com>
Date: Wed, 15 Jan 2025 15:24:16 -0500
Subject: [PATCH 1/3] Add files via upload

---
 .../o365_email_transport_rule_changed.yml     | 78 +++++++++++++++++++
 1 file changed, 78 insertions(+)
 create mode 100644 detections/cloud/o365_email_transport_rule_changed.yml

diff --git a/detections/cloud/o365_email_transport_rule_changed.yml b/detections/cloud/o365_email_transport_rule_changed.yml
new file mode 100644
index 0000000000..04398ee6a8
--- /dev/null
+++ b/detections/cloud/o365_email_transport_rule_changed.yml
@@ -0,0 +1,78 @@
+name: O365 Email Transport Rule Changed
+id: 11ebb7c2-46bd-41c9-81e1-d0b4b34583a2
+version: 1
+date: '2025-01-15'
+author: Steven Dick
+status: production
+type: Anomaly
+description: The following analytic identifies when a user with sufficient access to Exchange Online alters the mail flow/transport rule configuration of the organization. Transport rules are a set of rules that can be used by attackers to modify or delete emails based on specific conditions, this activity could indicate an attacker hiding or exfiltrated data.
+data_source: 
+- O365
+search: '`o365_management_activity` Workload=Exchange AND Operation IN ("Set-*","Disable-*","New-*","Remove-*") AND Operation="*TransportRule"
+| eval object_name = case('Parameters{}.Name'=="Name",mvindex('Parameters{}.Value',mvfind('Parameters{}.Name',"^Name$")),true(),ObjectId)
+| eval object_id = case('Parameters{}.Name'=="Identity",mvindex('Parameters{}.Value',mvfind('Parameters{}.Name',"^Identity$")),true(),Id)
+| stats values(object_name) as object_name, min(_time) as firstTime, max(_time) as lastTime, count by object_id, UserId, Operation
+| rename UserId as user, Operation as signature
+| `security_content_ctime(firstTime)` 
+| `security_content_ctime(lastTime)`
+| `o365_email_transport_rule_changed_filter`'
+how_to_implement: 
+known_false_positives: Legitimate administrative changes for business needs.
+references:
+- https://attack.mitre.org/techniques/T1114/003/
+- https://cardinalops.com/blog/cardinalops-contributes-new-mitre-attck-techniques-related-to-abuse-of-mail-transport-rules/
+- https://www.microsoft.com/en-us/security/blog/2022/09/22/malicious-OAuth-applications-used-to-compromise-email-servers-and-spread-spam/
+drilldown_searches:
+- name: View the detection results for - "$user$"
+  search: '%original_detection_search% | search user = "$user$"'
+  earliest_offset: $info_min_time$
+  latest_offset: $info_max_time$
+- name: View risk events for the last 7 days for - "$user$"
+  search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$user$") starthoursago=168  | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
+  earliest_offset: $info_min_time$
+  latest_offset: $info_max_time$
+- name: Investigate changes by $user$ 
+  search: '`o365_management_activity` Workload=Exchange AND Operation IN ("Set-*","Disable-*","New-*","Remove-*") AND Operation="*Transport*" UserId=$user$'
+  earliest_offset: $info_min_time$
+  latest_offset: $info_max_time$
+tags:
+  analytic_story: 
+  - Data Exfiltration
+  - Office 365 Account Takeover
+  asset_type: Cloud
+  confidence: 50
+  impact: 50
+  message: The user [$user$] altered the exchange transport rule id $object_id$ [$object_name$]
+  mitre_attack_id: 
+  - T1114.003
+  - T1564.008
+  observable: 
+  - name: user
+    type: user
+    role:
+    - Victim
+  - name: object_id
+    type: Other
+    role:
+    - Attacker
+  - name: object_name
+    type: Other
+    role:
+    - Attacker
+  product: 
+  - Splunk Enterprise
+  - Splunk Enterprise Security
+  - Splunk Cloud
+  required_fields: 
+  - Workload
+  - Operation
+  - UserId
+  - Parameters{}.Name
+  risk_score: 25
+  security_domain: threat
+tests:
+- name: True Positive Test
+  attack_data:
+  - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1114.003/transport_rule_change/transport_rule_change.log
+    source: o365
+    sourcetype: o365:management:activity
\ No newline at end of file

From 61dcaf1d290065ab1e556d482a3488a1448f60a9 Mon Sep 17 00:00:00 2001
From: Steven Dick <38897662+nterl0k@users.noreply.github.com>
Date: Wed, 15 Jan 2025 15:36:39 -0500
Subject: [PATCH 2/3] Update o365_email_transport_rule_changed.yml

probably single tick closeness to start problem in SPL
---
 detections/cloud/o365_email_transport_rule_changed.yml | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/detections/cloud/o365_email_transport_rule_changed.yml b/detections/cloud/o365_email_transport_rule_changed.yml
index 04398ee6a8..3a91b38470 100644
--- a/detections/cloud/o365_email_transport_rule_changed.yml
+++ b/detections/cloud/o365_email_transport_rule_changed.yml
@@ -8,9 +8,7 @@ type: Anomaly
 description: The following analytic identifies when a user with sufficient access to Exchange Online alters the mail flow/transport rule configuration of the organization. Transport rules are a set of rules that can be used by attackers to modify or delete emails based on specific conditions, this activity could indicate an attacker hiding or exfiltrated data.
 data_source: 
 - O365
-search: '`o365_management_activity` Workload=Exchange AND Operation IN ("Set-*","Disable-*","New-*","Remove-*") AND Operation="*TransportRule"
-| eval object_name = case('Parameters{}.Name'=="Name",mvindex('Parameters{}.Value',mvfind('Parameters{}.Name',"^Name$")),true(),ObjectId)
-| eval object_id = case('Parameters{}.Name'=="Identity",mvindex('Parameters{}.Value',mvfind('Parameters{}.Name',"^Identity$")),true(),Id)
+search: '`o365_management_activity` Workload=Exchange AND Operation IN ("Set-*","Disable-*","New-*","Remove-*") AND Operation="*TransportRule" | eval object_name = case('Parameters{}.Name'=="Name",mvindex('Parameters{}.Value',mvfind('Parameters{}.Name',"^Name$")),true(),ObjectId), object_id = case('Parameters{}.Name'=="Identity",mvindex('Parameters{}.Value',mvfind('Parameters{}.Name',"^Identity$")),true(),Id)
 | stats values(object_name) as object_name, min(_time) as firstTime, max(_time) as lastTime, count by object_id, UserId, Operation
 | rename UserId as user, Operation as signature
 | `security_content_ctime(firstTime)` 
@@ -75,4 +73,4 @@ tests:
   attack_data:
   - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1114.003/transport_rule_change/transport_rule_change.log
     source: o365
-    sourcetype: o365:management:activity
\ No newline at end of file
+    sourcetype: o365:management:activity

From c0de38c353023aeb89f81f1ef44f655f0b3bd07a Mon Sep 17 00:00:00 2001
From: Steven Dick <38897662+nterl0k@users.noreply.github.com>
Date: Wed, 15 Jan 2025 15:39:31 -0500
Subject: [PATCH 3/3] Update o365_email_transport_rule_changed.yml

---
 detections/cloud/o365_email_transport_rule_changed.yml | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/detections/cloud/o365_email_transport_rule_changed.yml b/detections/cloud/o365_email_transport_rule_changed.yml
index 3a91b38470..078d2c843c 100644
--- a/detections/cloud/o365_email_transport_rule_changed.yml
+++ b/detections/cloud/o365_email_transport_rule_changed.yml
@@ -8,7 +8,8 @@ type: Anomaly
 description: The following analytic identifies when a user with sufficient access to Exchange Online alters the mail flow/transport rule configuration of the organization. Transport rules are a set of rules that can be used by attackers to modify or delete emails based on specific conditions, this activity could indicate an attacker hiding or exfiltrated data.
 data_source: 
 - O365
-search: '`o365_management_activity` Workload=Exchange AND Operation IN ("Set-*","Disable-*","New-*","Remove-*") AND Operation="*TransportRule" | eval object_name = case('Parameters{}.Name'=="Name",mvindex('Parameters{}.Value',mvfind('Parameters{}.Name',"^Name$")),true(),ObjectId), object_id = case('Parameters{}.Name'=="Identity",mvindex('Parameters{}.Value',mvfind('Parameters{}.Name',"^Identity$")),true(),Id)
+search: '`o365_management_activity` Workload=Exchange AND Operation IN ("Set-*","Disable-*","New-*","Remove-*") AND Operation="*TransportRule" 
+| eval object_name = case('Parameters{}.Name'=="Name",mvindex('Parameters{}.Value',mvfind('Parameters{}.Name',"^Name$")),true(),ObjectId), object_id = case('Parameters{}.Name'=="Identity",mvindex('Parameters{}.Value',mvfind('Parameters{}.Name',"^Identity$")),true(),Id)
 | stats values(object_name) as object_name, min(_time) as firstTime, max(_time) as lastTime, count by object_id, UserId, Operation
 | rename UserId as user, Operation as signature
 | `security_content_ctime(firstTime)`