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Detection rules › Sigma

Abuse of Service Permissions to Hide Services Via Set-Service

Status
test
Severity
high
Log source
product windows, category process_creation
Author
Nasreddine Bencherchali (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects usage of the "Set-Service" powershell cmdlet to configure a new SecurityDescriptor that allows a service to be hidden from other utilities such as "sc.exe", "Get-Service"...etc. (Works only in powershell 7)

MITRE ATT&CK coverage

TacticTechniques
ExecutionT1574.011 Hijack Execution Flow: Services Registry Permissions Weakness
StealthT1574.011 Hijack Execution Flow: Services Registry Permissions Weakness

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation

Rule body yaml

title: Abuse of Service Permissions to Hide Services Via Set-Service
id: 514e4c3a-c77d-4cde-a00f-046425e2301e
related:
    - id: a537cfc3-4297-4789-92b5-345bfd845ad0
      type: derived
    - id: 953945c5-22fe-4a92-9f8a-a9edc1e522da
      type: similar
status: test
description: Detects usage of the "Set-Service" powershell cmdlet to configure a new SecurityDescriptor that allows a service to be hidden from other utilities such as "sc.exe", "Get-Service"...etc. (Works only in powershell 7)
references:
    - https://twitter.com/Alh4zr3d/status/1580925761996828672
    - https://learn.microsoft.com/en-us/powershell/module/microsoft.powershell.management/set-service?view=powershell-7.2
author: Nasreddine Bencherchali (Nextron Systems)
date: 2022-10-17
tags:
    - attack.persistence
    - attack.privilege-escalation
    - attack.execution
    - attack.stealth
    - attack.t1574.011
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\pwsh.exe'
        - OriginalFileName: 'pwsh.dll'
    selection_sddl:
        # Example would be: "D:(D;;DCLCWPDTSD;;;IU)(D;;DCLCWPDTSD;;;SU)(D;;DCLCWPDTSD;;;BA)(A;;CCLCSWLOCRRC;;;IU)(A;;CCLCSWLOCRRC;;;SU)(A;;CCLCSWRPWPDTLOCRRC;;;SY)(A;;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;BA)S:(AU;FA;CCDCLCSWRPWPDTLOCRSDRCWDWO;;;WD)"
        CommandLine|contains|all:
            - 'Set-Service '
            - 'DCLCWPDTSD'
    selection_cmdlet:
        CommandLine|contains:
            - '-SecurityDescriptorSddl '
            - '-sd '
    condition: all of selection_*
falsepositives:
    - Rare intended use of hidden services
level: high

Stages and Predicates

Stage 0: condition

all of selection_*

Stage 1: selection_img

selection_img:
    - Image|endswith: '\pwsh.exe'
    - OriginalFileName: 'pwsh.dll'

Stage 2: selection_sddl

selection_sddl:
    CommandLine|contains|all:
        - 'Set-Service '
        - 'DCLCWPDTSD'

Stage 3: selection_cmdlet

selection_cmdlet:
    CommandLine|contains:
        - '-SecurityDescriptorSddl '
        - '-sd '

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
CommandLinematch
  • -SecurityDescriptorSddl corpus 2 (sigma 2)
  • -sd corpus 2 (sigma 2)
  • DCLCWPDTSD corpus 2 (sigma 2)
  • Set-Service corpus 2 (sigma 2)
Imageends_with
  • \pwsh.exe corpus 168 (sigma 168)
OriginalFileNameeq
  • pwsh.dll corpus 112 (sigma 79, splunk 30, elastic 3)