Detection rules › Splunk

Windows Multiple Accounts Deleted

Status
production
Severity
medium
Group by
LogonId, SubjectDomainName, TargetDomainName, _time, signature, signature_id, user
Author
Mauricio Velazco, Splunk
Source
github.com/splunk/security_content

The following analytic detects the deletion of more than five unique Windows accounts within a 10-minute period, using Event Code 4726 from the Windows Security Event Log. It leverages the wineventlog_security dataset, segmenting data into 10-minute intervals to identify suspicious account deletions. This activity is significant as it may indicate an attacker attempting to erase traces of their actions. If confirmed malicious, this could lead to unauthorized access removal, hindering incident response and forensic investigations.

MITRE ATT&CK coverage

Event coverage

ProviderEventTitle
Security-AuditingEvent ID 4726A user account was deleted.

Rule body splunk

name: Windows Multiple Accounts Deleted
id: 49c0d4d6-c55d-4d3a-b3d5-7709fafed70d
version: 11
creation_date: '2024-03-06'
modification_date: '2026-05-13'
author: Mauricio Velazco, Splunk
status: production
type: TTP
description: The following analytic detects the deletion of more than five unique Windows accounts within a 10-minute period, using Event Code 4726 from the Windows Security Event Log. It leverages the `wineventlog_security` dataset, segmenting data into 10-minute intervals to identify suspicious account deletions. This activity is significant as it may indicate an attacker attempting to erase traces of their actions. If confirmed malicious, this could lead to unauthorized access removal, hindering incident response and forensic investigations.
data_source:
    - Windows Event Log Security 4726
search: |-
    `wineventlog_security` EventCode=4726 status=success
      | bucket span=10m _time
      | stats count dc(user) as unique_users values(user) as user values(dest) as dest
        BY EventCode signature _time
           src_user SubjectDomainName TargetDomainName
           Logon_ID
      | where unique_users > 5
      | `windows_multiple_accounts_deleted_filter`
how_to_implement: To successfully implement this search, you need to be ingesting Domain Controller events with the Windows TA. The Advanced Security Audit policy setting `Audit User Account Management` within `Account Management` needs to be enabled.
known_false_positives: Service accounts may be responsible for the creation, deletion or modification of accounts for legitimate purposes. Filter as needed.
references:
    - https://attack.mitre.org/techniques/T1098/
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: User $src_user$ deleted multiple accounts in a short period of time.
    entity:
        field: src_user
        type: user
        score: 50
analytic_story:
    - Azure Active Directory Persistence
asset_type: Endpoint
mitre_attack_id:
    - T1098
    - T1078
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/T1098/windows_multiple_accounts_deleted/windows_multiple_accounts_deleted.log
          source: XmlWinEventLog:Security
          sourcetype: XmlWinEventLog
      test_type: unit

Stages and Predicates

Stage 1: search

`wineventlog_security` EventCode=4726 status=success

Stage 2: bucket

| bucket span=10m _time

Stage 3: stats

| stats count dc(user) as unique_users values(user) as user values(dest) as dest
    BY EventCode signature _time
       src_user SubjectDomainName TargetDomainName
       Logon_ID

Stage 4: where

| where unique_users > 5

Stage 5: search

| `windows_multiple_accounts_deleted_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.

FieldKindValues
EventCodeeq
  • 4726 corpus 2 (splunk 1, kusto 1)
statuseq
  • success corpus 19 (sigma 16, splunk 3)
unique_usersgt
  • 5 corpus 3 (splunk 3)