detection.wiki

Detection rules › Sigma

PowerShell Set-Acl On Windows Folder

Severity
high
Author
Nasreddine Bencherchali (Nextron Systems)
Source
upstream

Detects PowerShell scripts to set the ACL to a file in the Windows folder

Event coverage

ProviderEvent IDTitle
Sysmon1Process creation

Stages and Predicates

Stage 1: all of selection_img

or:
Image|endswith: '\powershell.exe'
Image|endswith: '\pwsh.exe'
OriginalFileName: PowerShell.EXE
OriginalFileName: pwsh.dll

Stage 2: all of selection_cmdlet

CommandLine|contains: '-AclObject '
CommandLine|contains: 'Set-Acl '

Stage 3: all of selection_paths

or:
CommandLine|contains: '-Path $env:windir'
CommandLine|contains: '-Path %windir%'
CommandLine|contains: '-Path ''C:\Windows'
CommandLine|contains: '-Path "C:\Windows'

Stage 4: all of selection_permissions

or:
CommandLine|contains: Allow
CommandLine|contains: FullControl

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
  • -AclObject corpus 2 (sigma 2)
  • -Path "C:\Windows
  • -Path $env:windir
  • -Path %windir%
  • -Path 'C:\Windows
  • Allow corpus 2 (sigma 2)
  • FullControl
  • Set-Acl corpus 2 (sigma 2)
Imageends_with
  • \powershell.exe corpus 143 (sigma 143)
  • \pwsh.exe corpus 140 (sigma 140)
OriginalFileNameeq
  • PowerShell.EXE corpus 64 (sigma 60, splunk 4)
  • pwsh.dll corpus 72 (sigma 68, splunk 4)