Windows AD GPO Deleted

Status: production
Severity: medium
Group by: LogonId, ObjectDN, OpCorrelationID
Author: Dean Luxton
Source: github.com/splunk/security_content

This detection identifies when an Active Directory Group Policy is deleted using the Group Policy Management Console.

MITRE ATT&CK coverage

Tactic	Techniques
Privilege Escalation	`T1484.001` Domain or Tenant Policy Modification: Group Policy Modification
Defense Impairment	`T1484.001` Domain or Tenant Policy Modification: Group Policy Modification, `T1685` Disable or Modify Tools

Event coverage

Provider	Event	Title
Security-Auditing	Event ID 5136	A directory service object was modified.

Rule body splunk

name: Windows AD GPO Deleted
id: 0d41772b-35ab-4e1c-a2ba-d0b455481aee
version: 12
creation_date: '2024-07-01'
modification_date: '2026-05-13'
author: Dean Luxton
status: production
type: TTP
description: This detection identifies when an Active Directory Group Policy is deleted using the Group Policy Management Console.
data_source:
    - Windows Event Log Security 5136
search: |-
    `wineventlog_security` EventCode=5136 AttributeLDAPDisplayName=gpLink
      | eval  ObjectDN=upper(ObjectDN)
      | stats min(_time) as eventTime values(eval(if(OperationType=="%%14675",AttributeValue,null))) as old_value values(eval(if(OperationType=="%%14674",AttributeValue,null))) as new_value values(OperationType) as OperationType values(src_user) as src_user values(dest) as dest
        BY OpCorrelationID ObjectDN SubjectLogonId
      | rex field=old_value max_match=10000 "(?i)LDAP://(?P<old_dn>cn.*?);(?P<old_flag>\d)\]"
      | rex field=new_value max_match=10000 "(?i)LDAP://(?P<new_dn>cn.*?);(?P<new_flag>\d)\]"
      | mvexpand old_dn
      | where NOT old_dn IN (new_dn)
      | eval ObjectDN=upper(old_dn)
      | join ObjectDN type=outer [
      | search `admon` objectCategory="CN=Group-Policy-Container*" admonEventType=Update
      | eval ObjectDN=upper(distinguishedName)
      | stats latest(displayName) as displayName
        BY ObjectDN ]
      | stats min(eventTime) as _time values(OpCorrelationID) as OpCorrelationID values(displayName) as policyName values(src_user) as src_user
        BY ObjectDN SubjectLogonId
      | `windows_ad_gpo_deleted_filter`
how_to_implement: Ensure you are ingesting Active Directory audit logs - specifically event 5136, admon data is also used to display the display name of the GPO. See lantern article in references for further on how to onboard AD audit data. Ensure the wineventlog_security and admon macros are configured with the correct indexes.
known_false_positives: No false positives have been identified at this time.
references:
    - https://lantern.splunk.com/Security/Product_Tips/Enterprise_Security/Enabling_an_audit_trail_from_Active_Directory
drilldown_searches:
    - name: View the detection results for - "$src_user$"
      search: '%original_detection_search% | search  src_user = "$src_user$"'
      earliest_offset: $info_min_time$
      latest_offset: $info_max_time$
    - name: View risk events for the last 7 days for - "$src_user$"
      search: '| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$src_user$") | 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"
finding:
    title: GPO $policyName$ was deleted by $src_user$
    entity:
        field: src_user
        type: user
        score: 50
analytic_story:
    - Sneaky Active Directory Persistence Tricks
asset_type: Endpoint
mitre_attack_id:
    - T1685
    - T1484.001
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1484.001/group_policy_deleted/windows-security.log
          source: XmlWinEventLog:Security
          sourcetype: XmlWinEventLog
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1484.001/group_policy_deleted/windows-admon.log
          source: ActiveDirectory
          sourcetype: ActiveDirectory
      test_type: unit

Stages and Predicates

Stage 1: `search`

`wineventlog_security` EventCode=5136 AttributeLDAPDisplayName=gpLink

Stage 2: `eval`

| eval  ObjectDN=upper(ObjectDN)

Stage 3: `stats`

| stats min(_time) as eventTime values(eval(if(OperationType=="%%14675",AttributeValue,null))) as old_value values(eval(if(OperationType=="%%14674",AttributeValue,null))) as new_value values(OperationType) as OperationType values(src_user) as src_user values(dest) as dest
    BY OpCorrelationID ObjectDN SubjectLogonId

Stage 4: `rex`

| rex field=old_value max_match=10000 "(?i)LDAP://(?P<old_dn>cn.*?);(?P<old_flag>\d)\]"

Stage 5: `rex`

| rex field=new_value max_match=10000 "(?i)LDAP://(?P<new_dn>cn.*?);(?P<new_flag>\d)\]"

Stage 6: `mvexpand`

| mvexpand old_dn

Stage 7: `where`

| where NOT old_dn IN (new_dn)

Stage 8: `eval`

| eval ObjectDN=upper(old_dn)

Stage 9: `join`

| join ObjectDN type=outer [
  | search `admon` objectCategory="CN=Group-Policy-Container*" admonEventType=Update
  | eval ObjectDN=upper(distinguishedName)
  | stats latest(displayName) as displayName
    BY ObjectDN ]

Stage 10: `stats`

| stats min(eventTime) as _time values(OpCorrelationID) as OpCorrelationID values(displayName) as policyName values(src_user) as src_user
    BY ObjectDN SubjectLogonId

Stage 11: `search`

| `windows_ad_gpo_deleted_filter`

Exclusions

Top-level NOT(...) conjuncts: predicates this rule actively suppresses.

Field	Kind	Excluded values
`old_dn`	eq	`new_dn`

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
`AttributeLDAPDisplayName`	eq	`gpLink`
`EventCode`	eq	`5136` corpus 30 (splunk 24, kusto 5, elastic 1)
`admonEventType`	eq	`Update` corpus 5 (splunk 5)
`objectCategory`	eq	`"CN=Group-Policy-Container*"` corpus 3 (splunk 3)

`j` / `k`	Scroll down / up
`d` / `u`	Half-page down / up
`gg` / `G`	Top / bottom
`h` / `l`	History back / forward
`f`	Follow link (`Shift` = new tab)
`/`	Focus search
`?`	Toggle this help
`↑` / `↓`	Navigate search results
`Enter`	Open highlighted result
`Esc`	Close results / dialog

`type:`	`events` / `rules` / `providers`
`vendor:`	`sigma` / `elastic` / `splunk` / `kusto` / `chronicle` (vendor name alone also works: `sigma:`, `kql:`, `secops:`…)
`tactic:`	TA-id, slug, or name: `credential_access`, `TA0006`
`technique:`	technique or sub-technique ID: `T1003`, `T1003.001` (alias `tech:`)
`severity:`	`critical` / `high` / `medium` / `low` / `informational` (alias `sev:`)
`risk_score`	Numeric comparison on the Elastic risk score (0 to 100): `risk_score>50`, `risk_score<=20`, `risk_score=99` (alias `risk`; Elastic rules only)
`stages:`	Rules with exactly N pipeline stages
`correlation:`	`single_event` / `sequence` / `alternatives` / `alternatives_cross_log` / `all_required` / `correlated`
`with:`	Co-occurrence event-id; stacks (`with:4624 with:4769`) to require all, while a comma list in one occurrence (`with:4624,4769`) is an either-or group. Implies multi-event
`like:`	Structural neighbors of a rule slug (equivalents + subsumption stricter / broader): `like:comsvcs_lsass_memory_dump-splunk-sysmon`
`groupby:`	Entity-grouping substring match against `group_by_keys`: `groupby:user`, `groupby:host`
`uses:`	Rules whose predicate tree touches the field (any kind, any value): `uses:CommandLine`
`excludes:`	Rules with top-level `not()` clauses on the field (FP whitelists): `excludes:ParentImage`
`field:` / `value:`	Predicate search; narrows rule cards to those with a matching leaf and drives the indicator tier. Unquoted = substring, wildcards allowed (`value:mimikatz`)
`indicator:`	Shorthand for `field:F value:V`: `indicator:Image=*\powershell.exe`
`kind:`	Filter by predicate kind. Narrows rule cards to those carrying a matching predicate leaf (`vendor:elastic kind:cidr_match`) and drives the indicator tier: `contains` / `starts_with` / `ends_with` / `regex` / `cidr` / `eq` / `in` … (operator aliases `op:`/`match:`)
`has:` / `no:`	`sample`, `field`, `notes`, `refs`, `trace`, `thirdparty`, `rule`, `pattern`, `timewindow`, `threshold`, `newterms`, `sigma`/`elastic`/`splunk`/`kusto`/`chronicle`
`-op:val`	Exclude matches; works on most operators but not `type:`/`like:`/`has:`/`no:` (use `no:<flag>` to exclude a rule flag): `tactic:execution -vendor:splunk`. Standalone `-kind:`/`-field:`/`-value:` drop every rule carrying a matching predicate leaf (`type:rules -kind:is_null`)
`field:"…"` / `value:"…"`	Quoted value = anchored exact match (also allows spaces): `value:"net user"`
`a,b`	Comma = OR inside one operator (`vendor:sigma,elastic`, `severity:high,critical`); repeating a facet merges the same way. `field:`/`value:` never split (literal commas)
`vendors:` / `stage:`	Singular and plural spellings fold to the canonical operator and value: `tactics:` = `tactic:`, `type:event` = `type:events`, `correlation:sequences` = `correlation:sequence`, `has:thresholds` = `has:threshold`
`"quoted phrase"`	Exact-match a multi-word phrase (free text)

Windows AD GPO Deleted

MITRE ATT&CK coverage

Event coverage

Rule body splunk

Stages and Predicates

Stage 1: `search`

Stage 2: `eval`

Stage 3: `stats`

Stage 4: `rex`

Stage 5: `rex`

Stage 6: `mvexpand`

Stage 7: `where`

Stage 8: `eval`

Stage 9: `join`

Stage 10: `stats`

Stage 11: `search`

Exclusions

Indicators

Keyboard shortcuts

Search operators

Windows AD GPO Deleted

MITRE ATT&CK coverage

Event coverage

Rule body splunk

Stages and Predicates

Stage 1: search

Stage 2: eval

Stage 3: stats

Stage 4: rex

Stage 5: rex

Stage 6: mvexpand

Stage 7: where

Stage 8: eval

Stage 9: join

Stage 10: stats

Stage 11: search

Exclusions

Indicators

Stage 1: `search`

Stage 2: `eval`

Stage 3: `stats`

Stage 4: `rex`

Stage 5: `rex`

Stage 6: `mvexpand`

Stage 7: `where`

Stage 8: `eval`

Stage 9: `join`

Stage 10: `stats`

Stage 11: `search`