Potential APT FIN7 Exploitation Activity

Status: test
Severity: medium
Log source: category process_creation, product windows
Author: Alex Walston (@4ayymm)
Source: github.com/SigmaHQ/sigma

Detects potential APT FIN7 exploitation activity as reported by Google. In order to obtain initial access, FIN7 used compromised Remote Desktop Protocol (RDP) credentials to login to a target server and initiate specific Windows process chains.

Known false positives

Notepad++ can legitimately spawn cmd (Open Containing Folder in CMD)

MITRE ATT&CK coverage

Tactic	Techniques
Execution	`T1059.001` Command and Scripting Interpreter: PowerShell `T1059.003` Command and Scripting Interpreter: Windows Command Shell

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: Potential APT FIN7 Exploitation Activity
id: 6676896b-2cce-422d-82af-5a1abe65e241
status: test
description: |
    Detects potential APT FIN7 exploitation activity as reported by Google.
    In order to obtain initial access, FIN7 used compromised Remote Desktop Protocol (RDP) credentials to login to a target server and initiate specific Windows process chains.
references:
    - https://cloud.google.com/blog/topics/threat-intelligence/evolution-of-fin7/
author: Alex Walston (@4ayymm)
date: 2024-07-29
tags:
    - attack.execution
    - attack.t1059.001
    - attack.t1059.003
    - detection.emerging-threats
logsource:
    category: process_creation
    product: windows
detection:
    selection_notepad_plus:
        ParentImage|endswith: '\notepad++.exe'
        Image|endswith: '\cmd.exe'
    selection_rdpinit:
        ParentImage|endswith: '\rdpinit.exe'
        Image|endswith: '\notepad++.exe'
    condition: 1 of selection_*
falsepositives:
    - Notepad++ can legitimately spawn cmd (Open Containing Folder in CMD)
level: medium

Stages and Predicates

Stage 0: `condition`

1 of selection_*

Stage 1: `selection_notepad_plus`

selection_notepad_plus:
    ParentImage|endswith: '\notepad++.exe'
    Image|endswith: '\cmd.exe'

Stage 2: `selection_rdpinit`

selection_rdpinit:
    ParentImage|endswith: '\rdpinit.exe'
    Image|endswith: '\notepad++.exe'

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`Image`	ends_with	`\cmd.exe` corpus 130 (sigma 130) `\notepad++.exe`	`field:"Image" kind:ends_with`
`ParentImage`	ends_with	`\notepad++.exe` `\rdpinit.exe`	`field:"ParentImage" kind:ends_with`