Suspicious Remote Thread Target

SIGMA detection rule by Florian Roth (Nextron Systems) · NOASSERTION

Offensive tradecraft is switching away from using APIs like "CreateRemoteThread", however, this is still largely observed in the wild. This rule aims to detect suspicious processes (those we would not expect to behave in this way like winword.exe or outlook.exe) creating remote threads on other processes. It is a generalistic rule, but it should have a low FP ratio due to the selected range of processes.

title: Suspicious Remote Thread Target
id: f016c716-754a-467f-a39e-63c06f773987
status: deprecated
description: |
  Offensive tradecraft is switching away from using APIs like "CreateRemoteThread", however, this is still largely observed in the wild.
  This rule aims to detect suspicious processes (those we would not expect to behave in this way like winword.exe or outlook.exe) creating remote threads on other processes.
  It is a generalistic rule, but it should have a low FP ratio due to the selected range of processes.
references:
    - https://www.microsoft.com/security/blog/2022/08/24/looking-for-the-sliver-lining-hunting-for-emerging-command-and-control-frameworks/
author: Florian Roth (Nextron Systems)
date: 2022/08/25
modified: 2023/05/05
logsource:
    product: windows
    category: create_remote_thread
detection:
    selection:
        TargetImage|endswith:
            - '\spoolsv.exe'
            - '\notepad.exe'
    filter:
        - SourceImage|endswith: '\csrss.exe'
        - SourceImage|contains: 'unknown process'
        - StartFunction: 'EtwpNotificationThread'
    condition: selection and not filter
fields:
    - ComputerName
    - User
    - SourceImage
    - TargetImage
falsepositives:
    - Unknown
level: medium

[[ currentRule.title && currentRule.title.length > 60 ? currentRule.title.slice(0, 60) + '…' : currentRule.title ]]

b4ec60c5-e291-4e1d-9c24-efd8dd451143

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Executable code, not a declarative rule

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