Sigma Rule Library

Potential Devil Bait Related Indicator

Detects the creation of ".xml" and ".txt" files in folders of the "\AppData\Roaming\Microsoft" directory by uncommon processes. This behavior was seen common across different Devil Bait samples and stages as described by the NCSC

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Detection logic

selection

Image|endswith:
  - \schtasks.exe
  - \wscript.exe
  - \mshta.exe
TargetFilename|contains: \AppData\Roaming\Microsoft\
TargetFilename|endswith:
  - .txt
  - .xml

Condition

selection

Raw YAML

title: Potential Devil Bait Related Indicator
id: 93d5f1b4-36df-45ed-8680-f66f242b8415
status: test
description: Detects the creation of ".xml" and ".txt" files in folders of the "\AppData\Roaming\Microsoft" directory by uncommon processes. This behavior was seen common across different Devil Bait samples and stages as described by the NCSC
references:
    - https://www.ncsc.gov.uk/static-assets/documents/malware-analysis-reports/devil-bait/NCSC-MAR-Devil-Bait.pdf
author: Nasreddine Bencherchali (Nextron Systems)
date: 2023-05-15
tags:
    - detection.emerging-threats
    - attack.stealth
logsource:
    product: windows
    category: file_event
detection:
    selection:
        Image|endswith:
            - '\schtasks.exe'
            - '\wscript.exe'
            - '\mshta.exe'
        # Example folders used by the samples include:
        #   - %AppData%\Microsoft\Network\
        #   - %AppData%\Microsoft\Office\
        TargetFilename|contains: '\AppData\Roaming\Microsoft\'
        TargetFilename|endswith:
            - '.txt'
            - '.xml'
    condition: selection
falsepositives:
    - Unlikely
level: high

False positives

  • Unlikely

References

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