Detection rules › Sigma
User account creation disguised in a computer account
Detects scenarios where an attacker creates a user account that fakes a computer account.
MITRE ATT&CK coverage
| Tactic | Techniques |
|---|---|
| Persistence | T1098 Account Manipulation, T1136 Create Account |
Event coverage
| Provider | Event | Title |
|---|---|---|
| Security-Auditing | Event ID 4720 | A user account was created. |
| Security-Auditing | Event ID 4781 | The name of an account was changed. |
Rule body yaml
title: User account creation disguised in a computer account
description: Detects scenarios where an attacker creates a user account that fakes a computer account.
references:
- https://github.com/mdecrevoisier/EVTX-to-MITRE-Attack/tree/master/TA0003-Persistence/T1136-Create%20account
- https://www.securonix.com/blog/securonix-threat-labs-security-advisory-threat-actors-target-mssql-servers-in-dbjammer-to-deliver-freeworld-ransomware/
tags:
- attack.persistence
- attack.t1098 # account manipulation
- attack.t1136 # user creation
- attack.defense_evesion
- attack.t0136 # masquerading
author: mdecrevoisier
status: experimental
logsource:
product: windows
service: security
detection:
selection_creation:
EventID: 4720 # User account creation
TargetUserName|endswith: '$'
selection_renamed:
EventID: 4781 # User account name change
NewTargetUserName|endswith: '$'
filter:
OldTargetUserName|endswith: '$'
condition: selection_creation or (selection_renamed and not filter)
falsepositives:
- None
level: high
Stages and Predicates
Stage 0: condition
selection_creation or (selection_renamed and not filter)Stage 1: selection_creation
selection_creation:
EventID: 4720
TargetUserName|endswith: '$'
Stage 2: selection_renamed
selection_renamed:
EventID: 4781
NewTargetUserName|endswith: '$'
Stage 3: not filter
filter:
OldTargetUserName|endswith: '$'
Exclusions
Top-level NOT(...) conjuncts: predicates this rule actively suppresses.
| Field | Kind | Excluded values |
|---|---|---|
OldTargetUserName | ends_with | $ |
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 |
|---|---|---|
NewTargetUserName | ends_with |
|
TargetUserName | ends_with |
|