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Detection rules › Sigma

New File Association Using Exefile

Status
test
Severity
high
Log source
category registry_set, product windows
Author
Andreas Hunkeler (@Karneades)
Source
github.com/SigmaHQ/sigma

Detects the abuse of the exefile handler in new file association. Used for bypass of security products.

MITRE ATT&CK coverage

TacticTechniques
StealthNo specific technique

Telemetry coverage

ProviderRecord / event type
SysmonEvent ID 13: RegistryEvent (Value Set)

Rule body

title: New File Association Using Exefile
id: 44a22d59-b175-4f13-8c16-cbaef5b581ff
status: test
description: Detects the abuse of the exefile handler in new file association. Used for bypass of security products.
references:
    - https://twitter.com/mrd0x/status/1461041276514623491
author: Andreas Hunkeler (@Karneades)
date: 2021-11-19
modified: 2023-08-17
tags:
    - attack.stealth
logsource:
    category: registry_set
    product: windows
detection:
    selection:
        TargetObject|contains: 'Classes\.'
        Details: 'exefile'
    condition: selection
falsepositives:
    - Unknown
level: high

Stages and Predicates

Stage 0: condition

selection

Stage 1: selection

selection:
    TargetObject|contains: 'Classes\.'
    Details: 'exefile'

Indicators

These rows show field, operator, and value matches.

FieldKindValuesSearch
Detailseq
  • exefile
field:"Details" kind:eq value:"exefile"
TargetObjectmatch
  • Classes\.
field:"TargetObject" kind:match value:"Classes\."