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Detection rules › Sigma

Powershell LocalAccount Manipulation

Status
test
Severity
medium
Log source
product windows, category ps_script
Author
frack113
Source
github.com/SigmaHQ/sigma

Adversaries may manipulate accounts to maintain access to victim systems. Account manipulation may consist of any action that preserves adversary access to a compromised account, such as modifying credentials or permission groups

MITRE ATT&CK coverage

TacticTechniques
PersistenceT1098 Account Manipulation
Privilege EscalationT1098 Account Manipulation

Event coverage

ProviderEventTitle
PowerShellEvent ID 4104Creating Scriptblock text (MessageNumber of MessageTotal).

Rule body yaml

title: Powershell LocalAccount Manipulation
id: 4fdc44df-bfe9-4fcc-b041-68f5a2d3031c
status: test
description: |
    Adversaries may manipulate accounts to maintain access to victim systems.
    Account manipulation may consist of any action that preserves adversary access to a compromised account, such as modifying credentials or permission groups
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1098/T1098.md#atomic-test-1---admin-account-manipulate
    - https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.localaccounts/?view=powershell-5.1
author: frack113
date: 2021-12-28
tags:
    - attack.privilege-escalation
    - attack.persistence
    - attack.t1098
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection:
        ScriptBlockText|contains:
            - 'Disable-LocalUser'
            - 'Enable-LocalUser'
            - 'Get-LocalUser'
            - 'Set-LocalUser'
            - 'New-LocalUser'
            - 'Rename-LocalUser'
            - 'Remove-LocalUser'
    condition: selection
falsepositives:
    - Legitimate administrative script
level: medium

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    ScriptBlockText|contains:
        - 'Disable-LocalUser'
        - 'Enable-LocalUser'
        - 'Get-LocalUser'
        - 'Set-LocalUser'
        - 'New-LocalUser'
        - 'Rename-LocalUser'
        - 'Remove-LocalUser'

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
ScriptBlockTextmatch
  • Disable-LocalUser
  • Enable-LocalUser
  • Get-LocalUser corpus 2 (sigma 1, splunk 1)
  • New-LocalUser corpus 2 (sigma 2)
  • Remove-LocalUser
  • Rename-LocalUser
  • Set-LocalUser