Potential Mfdetours.DLL Sideloading

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

Detects potential DLL sideloading of "mfdetours.dll". While using "mftrace.exe" it can be abused to attach to an arbitrary process and force load any DLL named "mfdetours.dll" from the current directory of execution.

Known false positives

Unlikely

MITRE ATT&CK coverage

Tactic	Techniques
Execution	`T1574.001` Hijack Execution Flow: DLL
Stealth	`T1574.001` Hijack Execution Flow: DLL

Telemetry coverage

Provider	Record / event type
Sysmon	Event ID 7: Image loaded

Rule body

title: Potential Mfdetours.DLL Sideloading
id: d2605a99-2218-4894-8fd3-2afb7946514d
status: test
description: Detects potential DLL sideloading of "mfdetours.dll". While using "mftrace.exe" it can be abused to attach to an arbitrary process and force load any DLL named "mfdetours.dll" from the current directory of execution.
references:
    - Internal Research
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-08-03
tags:
    - attack.persistence
    - attack.privilege-escalation
    - attack.execution
    - attack.stealth
    - attack.t1574.001
logsource:
    category: image_load
    product: windows
detection:
    selection:
        ImageLoaded|endswith: '\mfdetours.dll'
    filter_main_legit_path:
        ImageLoaded|contains: ':\Program Files (x86)\Windows Kits\10\bin\'
    condition: selection and not 1 of filter_main_*
falsepositives:
    - Unlikely
level: medium

Stages and Predicates

Stage 0: `condition`

selection and not 1 of filter_main_*

Stage 1: `selection`

selection:
    ImageLoaded|endswith: '\mfdetours.dll'

Stage 2: `not filter_main_legit_path`

filter_main_legit_path:
    ImageLoaded|contains: ':\Program Files (x86)\Windows Kits\10\bin\'

Exclusions

The rule actively suppresses these predicates.

Field	Kind	Excluded values	Search
`ImageLoaded`	match	`:\Program Files (x86)\Windows Kits\10\bin\`	`excludes:ImageLoaded` `field:"ImageLoaded" value:":\Program Files (x86)\Windows Kits\10\bin\"`

Indicators

These rows show field, operator, and value matches.

Field	Kind	Values	Search
`ImageLoaded`	ends_with	`\mfdetours.dll` corpus 2 (sigma 2)	`field:"ImageLoaded" kind:ends_with value:"\mfdetours.dll"`