PowerShell SAM Copy

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

Detects suspicious PowerShell scripts accessing SAM hives

Known false positives

Some rare backup scenarios
PowerShell scripts fixing HiveNightmare / SeriousSAM ACLs

MITRE ATT&CK coverage

Tactic	Techniques
Credential Access	`T1003.002` OS Credential Dumping: Security Account Manager

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 1: Process creation
Security-Auditing	Event ID 4688: A new process has been created.

Rule body

title: PowerShell SAM Copy
id: 1af57a4b-460a-4738-9034-db68b880c665
status: test
description: Detects suspicious PowerShell scripts accessing SAM hives
references:
    - https://twitter.com/splinter_code/status/1420546784250769408
author: Florian Roth (Nextron Systems)
date: 2021-07-29
modified: 2023-01-06
tags:
    - attack.credential-access
    - attack.t1003.002
logsource:
    category: process_creation
    product: windows
detection:
    selection_1:
        CommandLine|contains|all:
            - '\HarddiskVolumeShadowCopy'
            - 'System32\config\sam'
    selection_2:
        CommandLine|contains:
            - 'Copy-Item'
            - 'cp $_.'
            - 'cpi $_.'
            - 'copy $_.'
            - '.File]::Copy('
    condition: all of selection*
falsepositives:
    - Some rare backup scenarios
    - PowerShell scripts fixing HiveNightmare / SeriousSAM ACLs
level: high

Stages and Predicates

Stage 0: `condition`

all of selection*

Stage 1: `selection_1`

selection_1:
    CommandLine|contains|all:
        - '\HarddiskVolumeShadowCopy'
        - 'System32\config\sam'

Stage 2: `selection_2`

selection_2:
    CommandLine|contains:
        - 'Copy-Item'
        - 'cp $_.'
        - 'cpi $_.'
        - 'copy $_.'
        - '.File]::Copy('

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`CommandLine`	match	`.File]::Copy(` `Copy-Item` corpus 6 (sigma 5, chronicle 1) `System32\config\sam` `\HarddiskVolumeShadowCopy` `copy $_.` `cp $_.` `cpi $_.`	`field:"CommandLine" kind:match`

PowerShell SAM Copy

Known false positives

MITRE ATT&CK coverage

Telemetry coverage

Rule body

Stages and Predicates

Stage 0: condition

Stage 1: selection_1

Stage 2: selection_2

Indicators

Stage 0: `condition`

Stage 1: `selection_1`

Stage 2: `selection_2`