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Detection rules › Sigma

Powershell Install a DLL in System Directory

Status
test
Severity
high
Log source
product windows, category ps_script
Author
frack113, Nasreddine Bencherchali (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Uses PowerShell to install/copy a file into a system directory such as "System32" or "SysWOW64"

MITRE ATT&CK coverage

TacticTechniques
PersistenceT1556.002 Modify Authentication Process: Password Filter DLL
Defense ImpairmentT1556.002 Modify Authentication Process: Password Filter DLL
Credential AccessT1556.002 Modify Authentication Process: Password Filter DLL

Event coverage

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

Rule body yaml

title: Powershell Install a DLL in System Directory
id: 63bf8794-9917-45bc-88dd-e1b5abc0ecfd
status: test
description: Uses PowerShell to install/copy a file into a system directory such as "System32" or "SysWOW64"
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1556.002/T1556.002.md#atomic-test-1---install-and-register-password-filter-dll
author: frack113, Nasreddine Bencherchali (Nextron Systems)
date: 2021-12-27
modified: 2024-01-22
tags:
    - attack.persistence
    - attack.credential-access
    - attack.defense-impairment
    - attack.t1556.002
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection:
        ScriptBlockText|re: '(Copy-Item|cpi) .{2,128} -Destination .{1,32}\\Windows\\(System32|SysWOW64)'
    condition: selection
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    ScriptBlockText|re: '(Copy-Item|cpi) .{2,128} -Destination .{1,32}\\Windows\\(System32|SysWOW64)'

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
ScriptBlockTextregex_match
  • (Copy-Item|cpi) .{2,128} -Destination .{1,32}\Windows\(System32|SysWOW64)