Detection rules › Sigma

Suspicious Microsoft Office Child Process - MacOS

Status
test
Severity
high
Log source
product macos, category process_creation
Author
Sohan G (D4rkCiph3r)
Source
github.com/SigmaHQ/sigma

Detects suspicious child processes spawning from microsoft office suite applications such as word or excel. This could indicates malicious macro execution

MITRE ATT&CK coverage

Event coverage

ProviderEventTitle
ESFexecProcess Execution (Notify)

Rule body yaml

title: Suspicious Microsoft Office Child Process - MacOS
id: 69483748-1525-4a6c-95ca-90dc8d431b68
status: test
description: Detects suspicious child processes spawning from microsoft office suite applications such as word or excel. This could indicates malicious macro execution
references:
    - https://redcanary.com/blog/applescript/
    - https://objective-see.org/blog/blog_0x4B.html
author: Sohan G (D4rkCiph3r)
date: 2023-01-31
modified: 2023-02-04
tags:
    - attack.execution
    - attack.persistence
    - attack.t1059.002
    - attack.t1137.002
    - attack.t1204.002
logsource:
    product: macos
    category: process_creation
detection:
    selection:
        ParentImage|contains:
            - 'Microsoft Word'
            - 'Microsoft Excel'
            - 'Microsoft PowerPoint'
            - 'Microsoft OneNote'
        Image|endswith:
            - '/bash'
            - '/curl'
            - '/dash'
            - '/fish'
            - '/osacompile'
            - '/osascript'
            - '/sh'
            - '/zsh'
            - '/python'
            - '/python3'
            - '/wget'
    condition: selection
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    ParentImage|contains:
        - 'Microsoft Word'
        - 'Microsoft Excel'
        - 'Microsoft PowerPoint'
        - 'Microsoft OneNote'
    Image|endswith:
        - '/bash'
        - '/curl'
        - '/dash'
        - '/fish'
        - '/osacompile'
        - '/osascript'
        - '/sh'
        - '/zsh'
        - '/python'
        - '/python3'
        - '/wget'

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
Imageends_with
  • /bash
  • /curl
  • /dash
  • /fish
  • /osacompile
  • /osascript
  • /python
  • /python3
  • /sh
  • /wget
  • /zsh
ParentImagematch
  • Microsoft Excel
  • Microsoft OneNote
  • Microsoft PowerPoint
  • Microsoft Word