sigmamediumHunting

DLL Execution via Rasautou.exe

Detects using Rasautou.exe for loading arbitrary .DLL specified in -d option and executes the export specified in -p.

MITRE ATT&CK

defense-evasion

Detection Query

selection_img:
  - Image|endswith: \rasautou.exe
  - OriginalFileName: rasdlui.exe
selection_cli:
  CommandLine|contains|all:
    - " -d "
    - " -p "
condition: all of selection*

Author

Julia Fomina, oscd.community

Created

2020-10-09

Data Sources

windowsProcess Creation Events

Platforms

windows

References

Tags

attack.defense-evasionattack.t1218

Raw Content

title: DLL Execution via Rasautou.exe
id: cd3d1298-eb3b-476c-ac67-12847de55813
status: test
description: Detects using Rasautou.exe for loading arbitrary .DLL specified in -d option and executes the export specified in -p.
references:
    - https://lolbas-project.github.io/lolbas/Binaries/Rasautou/
    - https://github.com/fireeye/DueDLLigence
    - https://www.fireeye.com/blog/threat-research/2019/10/staying-hidden-on-the-endpoint-evading-detection-with-shellcode.html
author: Julia Fomina, oscd.community
date: 2020-10-09
tags:
    - attack.defense-evasion
    - attack.t1218
logsource:
    product: windows
    category: process_creation
    definition: Since options '-d' and '-p' were removed in Windows 10 this rule is relevant only for Windows before 10. And as Windows 7 doesn't log command line in 4688 by default, to detect this attack you need Sysmon 1 configured or KB3004375 installed for command-line auditing (https://support.microsoft.com/en-au/help/3004375/microsoft-security-advisory-update-to-improve-windows-command-line-aud)
detection:
    selection_img:
        - Image|endswith: '\rasautou.exe'
        - OriginalFileName: 'rasdlui.exe'
    selection_cli:
        CommandLine|contains|all:
            - ' -d '
            - ' -p '
    condition: all of selection*
falsepositives:
    - Unlikely
level: medium