Detection rules › Sigma

Macro Enabled In A Potentially Suspicious Document

Status
test
Severity
high
Log source
product windows, category registry_set
Author
Nasreddine Bencherchali (Nextron Systems)
Source
github.com/SigmaHQ/sigma

Detects registry changes to Office trust records where the path is located in a potentially suspicious location

MITRE ATT&CK coverage

TacticTechniques
PersistenceT1112 Modify Registry
Defense ImpairmentT1112 Modify Registry

Event coverage

ProviderEventTitle
SysmonEvent ID 13RegistryEvent (Value Set)

Rule body yaml

title: Macro Enabled In A Potentially Suspicious Document
id: a166f74e-bf44-409d-b9ba-ea4b2dd8b3cd
related:
    - id: 295a59c1-7b79-4b47-a930-df12c15fc9c2
      type: derived
status: test
description: Detects registry changes to Office trust records where the path is located in a potentially suspicious location
references:
    - https://twitter.com/inversecos/status/1494174785621819397
    - Internal Research
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-06-21
modified: 2023-08-17
tags:
    - attack.persistence
    - attack.defense-impairment
    - attack.t1112
logsource:
    category: registry_set
    product: windows
detection:
    selection_value:
        TargetObject|contains: '\Security\Trusted Documents\TrustRecords'
    selection_paths:
        TargetObject|contains:
            # Note: add more locations where you don't expect a user to executed macro enabled docs
            - '/AppData/Local/Microsoft/Windows/INetCache/'
            - '/AppData/Local/Temp/'
            - '/PerfLogs/'
            - 'C:/Users/Public/'
            - 'file:///D:/'
            - 'file:///E:/'
    condition: all of selection_*
falsepositives:
    - Unlikely
level: high

Stages and Predicates

Stage 0: condition

all of selection_*

Stage 1: selection_value

selection_value:
    TargetObject|contains: '\Security\Trusted Documents\TrustRecords'

Stage 2: selection_paths

selection_paths:
    TargetObject|contains:
        - '/AppData/Local/Microsoft/Windows/INetCache/'
        - '/AppData/Local/Temp/'
        - '/PerfLogs/'
        - 'C:/Users/Public/'
        - 'file:///D:/'
        - 'file:///E:/'

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
TargetObjectmatch
  • /AppData/Local/Microsoft/Windows/INetCache/
  • /AppData/Local/Temp/
  • /PerfLogs/
  • C:/Users/Public/
  • \Security\Trusted Documents\TrustRecords corpus 2 (sigma 2)
  • file:///D:/
  • file:///E:/