Suspicious Files in Default GPO Folder

Status: test
Severity: medium
Log source: category file_event, product windows
Author: elhoim
Source: github.com/SigmaHQ/sigma

Detects the creation of copy of suspicious files (EXE/DLL) to the default GPO storage folder

MITRE ATT&CK coverage

Tactic	Techniques
Stealth	`T1036.005` Masquerading: Match Legitimate Resource Name or Location

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 11: FileCreate

Rule body

title: Suspicious Files in Default GPO Folder
id: 5f87308a-0a5b-4623-ae15-d8fa1809bc60
status: test
description: Detects the creation of copy of suspicious files (EXE/DLL) to the default GPO storage folder
references:
    - https://redcanary.com/blog/intelligence-insights-november-2021/
author: elhoim
date: 2022-04-28
tags:
    - attack.stealth
    - attack.t1036.005
logsource:
    product: windows
    category: file_event
detection:
    selection:
        TargetFilename|contains: '\Policies\{31B2F340-016D-11D2-945F-00C04FB984F9}\'
        TargetFilename|endswith:
            - '.dll'
            - '.exe'
    condition: selection
falsepositives:
    - Unknown
level: medium

Stages and Predicates

Stage 0: `condition`

selection

Stage 1: `selection`

selection:
    TargetFilename|contains: '\Policies\{31B2F340-016D-11D2-945F-00C04FB984F9}\'
    TargetFilename|endswith:
        - '.dll'
        - '.exe'

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`TargetFilename`	ends_with	`.dll` corpus 24 (sigma 24) `.exe` corpus 21 (sigma 20, splunk 1)	`field:"TargetFilename" kind:ends_with`
`TargetFilename`	match	`\Policies\{31B2F340-016D-11D2-945F-00C04FB984F9}\`	`field:"TargetFilename" kind:match value:"\Policies\{31B2F340-016D-11D2-945F-00C04FB984F9}\"`

Suspicious Files in Default GPO Folder

MITRE ATT&CK coverage

Telemetry coverage

Rule body

Stages and Predicates

Stage 0: condition

Stage 1: selection

Indicators

Stage 0: `condition`

Stage 1: `selection`