BITS Transfer Job Downloading File Potential Suspicious Extension — Sigma Rule

Rule metadata and linked tags

Author: frack113. Source status: test; severity: medium. Source dates: 2022-03-01 / 2023-03-27.

{
  "product": "windows",
  "service": "bits-client"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 36b40d167562b06a06814cd180a78dbe8b6532df4dbc3441dcf3e9882c642099

Detection logic

Original source YAML. Source-tag agreement is not proof of complete semantic coverage. This rule has not been compiled for a SIEM backend or validated against live telemetry here.

title: BITS Transfer Job Downloading File Potential Suspicious Extension
id: b85e5894-9b19-4d86-8c87-a2f3b81f0521
status: test
description: Detects new BITS transfer job saving local files with potential suspicious extensions
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1197/T1197.md
author: frack113
date: 2022-03-01
modified: 2023-03-27
tags:
    - attack.persistence
    - attack.execution
    - attack.stealth
    - attack.t1197
logsource:
    product: windows
    service: bits-client
detection:
    selection:
        EventID: 16403
        LocalName|endswith:
            # TODO: Extend this list with more interesting file extensions
            - '.bat'
            - '.dll'
            - '.exe' # TODO: Might wanna comment this if it generates tons of FPs
            - '.hta'
            - '.ps1'
            - '.psd1'
            - '.sh'
            - '.vbe'
            - '.vbs'
    filter_optional_generic:
        # Typical updates: Chrome, Dropbox etc.
        LocalName|contains: '\AppData\'
        RemoteName|contains: '.com'
    condition: selection and not 1 of filter_optional_*
falsepositives:
    - While the file extensions in question can be suspicious at times. It's best to add filters according to your environment to avoid large amount false positives
level: medium

Original YAML and metadata in JSON

False positives

• While the file extensions in question can be suspicious at times. It's best to add filters according to your environment to avoid large amount false positives

Source references

• https://github.com/redcanaryco/atomic-red-team/blob/f339e7da7d05f6057fdfcdd3742bfcf365fee2a9/atomics/T1197/T1197.md