detection.wiki

Detection rules › Sigma

Findstr GPP Passwords

Status
test
Severity
high
Log source
product windows, category process_creation
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

TacticTechniques
Credential AccessT1552.006 Unsecured Credentials: Group Policy Preferences

Event coverage

ProviderEventTitle
SysmonEvent ID 1Process creation

Rule body yaml

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

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
  • .xml corpus 6 (sigma 4, splunk 2)
  • \sysvol\ corpus 4 (sigma 4)
  • cpassword corpus 2 (sigma 1, splunk 1)
Imageends_with
  • \find.exe corpus 8 (sigma 8)
  • \findstr.exe corpus 12 (sigma 12)
OriginalFileNameeq
  • FIND.EXE corpus 7 (sigma 7)
  • FINDSTR.EXE corpus 12 (sigma 12)