Findstr GPP Passwords

Status: test
Severity: high
Log source: category process_creation, product windows
Author: frack113
Source: github.com/SigmaHQ/sigma

Look for the encrypted cpassword value within Group Policy Preference files on the Domain Controller. This value can be decrypted with gpp-decrypt.

MITRE ATT&CK coverage

Tactic	Techniques
Credential Access	`T1552.006` Unsecured Credentials: Group Policy Preferences

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 1: Process creation

Rule body

title: Findstr GPP Passwords
id: 91a2c315-9ee6-4052-a853-6f6a8238f90d
status: test
description: Look for the encrypted cpassword value within Group Policy Preference files on the Domain Controller. This value can be decrypted with gpp-decrypt.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1552.006/T1552.006.md#atomic-test-1---gpp-passwords-findstr
author: frack113
date: 2021-12-27
modified: 2023-11-11
tags:
    - attack.credential-access
    - attack.t1552.006
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith:
              - '\find.exe'
              - '\findstr.exe'
        - OriginalFileName:
              - 'FIND.EXE'
              - 'FINDSTR.EXE'
    selection_cli:
        CommandLine|contains|all:
            - 'cpassword'
            - '\sysvol\'
            - '.xml'
    condition: all of selection_*
falsepositives:
    - Unknown
level: high
regression_tests_path: regression_data/rules/windows/process_creation/proc_creation_win_findstr_gpp_passwords/info.yml
simulation:
    - type: atomic-red-team
      name: GPP Passwords (findstr)
      technique: T1552.006
      atomic_guid: 870fe8fb-5e23-4f5f-b89d-dd7fe26f3b5f

Stages and Predicates

Stage 0: `condition`

all of selection_*

Stage 1: `selection_img`

selection_img:
    - Image|endswith:
          - '\find.exe'
          - '\findstr.exe'
    - OriginalFileName:
          - 'FIND.EXE'
          - 'FINDSTR.EXE'

Stage 2: `selection_cli`

selection_cli:
    CommandLine|contains|all:
        - 'cpassword'
        - '\sysvol\'
        - '.xml'

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`CommandLine`	match	`.xml` corpus 6 (sigma 4, splunk 2) `\sysvol\` corpus 4 (sigma 4) `cpassword` corpus 2 (sigma 1, splunk 1)	`field:"CommandLine" kind:match`
`Image`	ends_with	`\find.exe` corpus 7 (sigma 7) `\findstr.exe` corpus 11 (sigma 11)	`field:"Image" kind:ends_with`
`OriginalFileName`	eq	`FIND.EXE` corpus 7 (sigma 7) `FINDSTR.EXE` corpus 12 (sigma 12)	`field:"OriginalFileName" kind:eq`

Findstr GPP Passwords

MITRE ATT&CK coverage

Telemetry coverage

Rule body

Stages and Predicates

Stage 0: condition

Stage 1: selection_img

Stage 2: selection_cli

Indicators

Stage 0: `condition`

Stage 1: `selection_img`

Stage 2: `selection_cli`