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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.

  • Type: TTP

  • Product: Splunk Enterprise, Splunk Enterprise Security, Splunk Cloud

  • Last Updated: 2024-05-21
  • Author: Mauricio Velazco, Splunk
  • ID: 49c0d4d6-c55d-4d3a-b3d5-7709fafed70d

Annotations

ATT&CK

ATT&CK

ID Technique Tactic
T1098 Account Manipulation Persistence, Privilege Escalation
T1078 Valid Accounts Defense Evasion, Persistence, Privilege Escalation, Initial Access
Kill Chain Phase
  • Installation
  • Exploitation
  • Delivery
NIST
  • DE.CM
CIS20
  • CIS 10
CVE 


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 `wineventlog_security` EventCode=4726 status=success 
| bucket span=10m _time 
| stats count dc(user) as unique_users values(user) as user by EventCode signature _time src_user SubjectDomainName TargetDomainName Logon_ID 
| where unique_users > 5 
| `windows_multiple_accounts_deleted_filter`

Macros

The SPL above uses the following Macros:

:information_source: windows_multiple_accounts_deleted_filter is a empty macro by default. It allows the user to filter out any results (false positives) without editing the SPL.

Required fields

List of fields required to use this analytic.

  • _time
  • EventCode
  • success
  • TargetUserName
  • SubjectUserName
  • src_user
  • SubjectDomainName
  • TargetDomainName
  • Logon_ID
  • user

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.

Associated Analytic Story

RBA

Risk Score Impact Confidence Message
18.0 30 60 User $src_user$ deleted multiple accounts in a short period of time.

:information_source: The Risk Score is calculated by the following formula: Risk Score = (Impact * Confidence/100). Initial Confidence and Impact is set by the analytic author.

Reference

Test Dataset

Replay any dataset to Splunk Enterprise by using our replay.py tool or the UI. Alternatively you can replay a dataset into a Splunk Attack Range

source | version: 2