detection.wiki

Detection rules › Sigma

Get-ADUser Enumeration Using UserAccountControl Flags

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

Detects AS-REP roasting is an attack that is often-overlooked. It is not very common as you have to explicitly set accounts that do not require pre-authentication.

MITRE ATT&CK coverage

TacticTechniques
DiscoveryT1033 System Owner/User Discovery

Event coverage

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

Rule body yaml

title: Get-ADUser Enumeration Using UserAccountControl Flags
id: 96c982fe-3d08-4df4-bed2-eb14e02f21c8
status: test
description: Detects AS-REP roasting is an attack that is often-overlooked. It is not very common as you have to explicitly set accounts that do not require pre-authentication.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1069.002/T1069.002.md#atomic-test-11---get-aduser-enumeration-using-useraccountcontrol-flags-as-rep-roasting
    - https://shellgeek.com/useraccountcontrol-flags-to-manipulate-properties/
author: frack113
date: 2022-03-17
tags:
    - attack.discovery
    - attack.t1033
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection:
        # 4194304 DONT_REQ_PREAUTH
        ScriptBlockText|contains|all:
            - 'Get-ADUser'
            - '-Filter'
            - 'useraccountcontrol'
            - '-band'
            - '4194304'
    condition: selection
falsepositives:
    - Legitimate PowerShell scripts
level: medium

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    ScriptBlockText|contains|all:
        - 'Get-ADUser'
        - '-Filter'
        - 'useraccountcontrol'
        - '-band'
        - '4194304'

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
  • -Filter corpus 3 (sigma 2, splunk 1)
  • -band
  • 4194304 corpus 2 (sigma 1, splunk 1)
  • Get-ADUser corpus 4 (sigma 2, splunk 2)
  • useraccountcontrol