Detection rules › Splunk
O365 ZAP Activity Detection
The following analytic detects when the Microsoft Zero-hour Automatic Purge (ZAP) capability takes action against a user's mailbox. This capability is an enhanced protection feature that retro-actively removes email with known malicious content for user inboxes. Since this is a retroactive capability, there is still a window in which the user may fall victim to the malicious content.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Initial Access | T1566.001 Phishing: Spearphishing Attachment, T1566.002 Phishing: Spearphishing Link |
Rules detecting the same action
Other rules on this platform that filter on the same API call or operation.
Rule body splunk
name: O365 ZAP Activity Detection
id: 4df275fd-a0e5-4246-8b92-d3201edaef7a
version: 12
creation_date: '2024-04-07'
modification_date: '2026-05-13'
author: Steven Dick
status: production
type: Anomaly
description: The following analytic detects when the Microsoft Zero-hour Automatic Purge (ZAP) capability takes action against a user's mailbox. This capability is an enhanced protection feature that retro-actively removes email with known malicious content for user inboxes. Since this is a retroactive capability, there is still a window in which the user may fall victim to the malicious content.
data_source:
- Office 365 Universal Audit Log
search: |-
`o365_management_activity` Workload=SecurityComplianceCenter Operation=AlertEntityGenerated Name="*messages containing malicious*"
| fromjson Data
| fillnull
| stats count min(_time) as firstTime max(_time) as lastTime values(zu) as url values(zfn) as file_name values(ms) as subject values(ttr) as result values(tsd) as src_user
BY AlertId,trc,signature,Name,dest,src,vendor_account,vendor_product
| rename Name as signature, AlertId as signature_id, trc as user
| eval action = CASE(match(result,"Success"), "blocked", true(),"allowed"), url = split(url,";")
| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `o365_zap_activity_detection_filter`
how_to_implement: You must install the Splunk Microsoft Office 365 Add-on and ingest Office 365 management activity events. Some features of Zero-hour purge are only offered within E3/E5 license level tenants, events may not be available otherwise.
known_false_positives: No false positives have been identified at this time.
references:
- https://learn.microsoft.com/en-us/microsoft-365/security/office-365-security/zero-hour-auto-purge?view=o365-worldwide
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 ("$user$") | 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: 7d
latest_offset: "0"
intermediate_findings:
entities:
- field: user
type: user
score: 20
message: User $user$ was included in a ZAP protection activity.
threat_objects:
- field: file_name
type: file_name
- field: src_user
type: email_address
- field: url
type: url
analytic_story:
- Spearphishing Attachments
- Suspicious Emails
asset_type: O365 Tenant
mitre_attack_id:
- T1566.001
- T1566.002
product:
- Splunk Enterprise
- Splunk Enterprise Security
- Splunk Cloud
category: cloud
security_domain: threat
tests:
- name: True Positive Test
attack_data:
- data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1566/o365_various_alerts/o365_various_alerts.log
sourcetype: o365:management:activity
source: o365
test_type: unit
Stages and Predicates
Stage 1: search
`o365_management_activity` Workload=SecurityComplianceCenter Operation=AlertEntityGenerated Name="*messages containing malicious*"
Stage 2: search
| fromjson Data
Stage 3: fillnull
| fillnull
Stage 4: stats
| stats count min(_time) as firstTime max(_time) as lastTime values(zu) as url values(zfn) as file_name values(ms) as subject values(ttr) as result values(tsd) as src_user
BY AlertId,trc,signature,Name,dest,src,vendor_account,vendor_product
Stage 5: rename
| rename Name as signature, AlertId as signature_id, trc as user
Stage 6: eval
| eval action = CASE(match(result,"Success"), "blocked", true(),"allowed"), url = split(url,";")
action =match(result, "Success")"blocked""allowed"Stage 7: search
| `security_content_ctime(firstTime)`
Stage 8: search
| `security_content_ctime(lastTime)`
Stage 9: search
| `o365_zap_activity_detection_filter`
Indicators
Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.
| Field | Kind | Values |
|---|---|---|
Name | eq |
|
Operation | eq |
|
Workload | eq |
|
sourcetype | eq |
|
Search terms
Bare-string tokens in the SPL search body. Splunk matches each token against _raw (the untyped raw event text) anywhere it appears, not against a specific field. These don't surface in the Indicators table because they aren't predicates on a known field.
| Stage | Term |
|---|---|
| 2 | fromjson |
| 2 | Data |