Detection rules › Sigma
Suspicious computer account created by a computer account
Detects scenarios where an attacker abuse MachineAccountQuota privilege and pre-create a computer object for abusing RBCD delegation.
Known false positives
- Offline domain join host
- Windows Autopilot Hybrid Azure AD Join
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Persistence |
Telemetry coverage
| Provider | Record / event type |
|---|---|
| Security-Auditing | Event ID 4741: A computer account was created. |
Rule body
title: Suspicious computer account created by a computer account
description: Detects scenarios where an attacker abuse MachineAccountQuota privilege and pre-create a computer object for abusing RBCD delegation.
references:
- https://dirkjanm.io/worst-of-both-worlds-ntlm-relaying-and-kerberos-delegation/
tags:
- attack.persistence
- attack.t1136
author: mdecrevoisier
status: experimental
logsource:
product: windows
service: security
detection:
selection:
EventID: 4741
SubjectUserName|endswith: '$'
SubjectUserSid|startswith: 'S-1-5-21-' # SYSTEM account 'S-1-5-18' would trigger a false positive
TargetUserName|endswith: '$'
condition: selection
falsepositives:
- Offline domain join host
- Windows Autopilot Hybrid Azure AD Join
level: high
Stages and Predicates
Stage 0: condition
selectionStage 1: selection
selection:
EventID: 4741
SubjectUserName|endswith: '$'
SubjectUserSid|startswith: 'S-1-5-21-'
TargetUserName|endswith: '$'
Indicators
These rows show field, operator, and value matches.
| Field | Kind | Values | Search |
|---|---|---|---|
SubjectUserName | ends_with |
| field:"SubjectUserName" kind:ends_with value:"$" |
SubjectUserSid | starts_with |
| field:"SubjectUserSid" kind:starts_with value:"S-1-5-21-" |
TargetUserName | ends_with |
| field:"TargetUserName" kind:ends_with value:"$" |