Detection rules › Sigma

Code Executed Via Office Add-in XLL File

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

Adversaries may abuse Microsoft Office add-ins to obtain persistence on a compromised system. Office add-ins can be used to add functionality to Office programs

MITRE ATT&CK coverage

Event coverage

Rule body yaml

title: Code Executed Via Office Add-in XLL File
id: 36fbec91-fa1b-4d5d-8df1-8d8edcb632ad
status: test
description: |
    Adversaries may abuse Microsoft Office add-ins to obtain persistence on a compromised system.
    Office add-ins can be used to add functionality to Office programs
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1137.006/T1137.006.md
author: frack113
date: 2021-12-28
tags:
    - attack.persistence
    - attack.t1137.006
logsource:
    product: windows
    category: ps_script
    definition: 'Requirements: Script Block Logging must be enabled'
detection:
    selection:
        ScriptBlockText|contains|all:
            - 'new-object '
            - '-ComObject '
            - '.application'
            - '.RegisterXLL'
    condition: selection
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    ScriptBlockText|contains|all:
        - 'new-object '
        - '-ComObject '
        - '.application'
        - '.RegisterXLL'

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
ScriptBlockTextmatch
  • -ComObject
  • .RegisterXLL
  • .application
  • new-object corpus 2 (sigma 2)