File With Suspicious Extension Downloaded Via Bitsadmin — Sigma Rule

Rule metadata and linked tags

Author: Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems). Source status: test; severity: high. Source dates: 2022-06-28 / 2023-05-30.

{
  "category": "process_creation",
  "product": "windows"
}

Pinned original Sigma rule · Detection Rule License 1.1

Source SHA-256: 7a862f3df49d08914053529dc5cf37e22509e8ea3fc0f4fac821c3cfaf6ccf79

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: File With Suspicious Extension Downloaded Via Bitsadmin
id: 5b80a791-ad9b-4b75-bcc1-ad4e1e89c200
status: test
description: Detects usage of bitsadmin downloading a file with a suspicious extension
references:
    - https://blog.netspi.com/15-ways-to-download-a-file/#bitsadmin
    - https://isc.sans.edu/diary/22264
    - https://lolbas-project.github.io/lolbas/Binaries/Bitsadmin/
author: Florian Roth (Nextron Systems), Nasreddine Bencherchali (Nextron Systems)
date: 2022-06-28
modified: 2023-05-30
tags:
    - attack.persistence
    - attack.execution
    - attack.stealth
    - attack.t1197
    - attack.s0190
    - attack.t1036.003
    - attack.command-and-control
    - attack.t1105
logsource:
    category: process_creation
    product: windows
detection:
    selection_img:
        - Image|endswith: '\bitsadmin.exe'
        - OriginalFileName: 'bitsadmin.exe'
    selection_flags:
        CommandLine|contains:
            - ' /transfer '
            - ' /create '
            - ' /addfile '
    selection_extension:
        CommandLine|contains:
            - '.7z'
            - '.asax'
            - '.ashx'
            - '.asmx'
            - '.asp'
            - '.aspx'
            - '.bat'
            - '.cfm'
            - '.cgi'
            - '.chm'
            - '.cmd'
            - '.dll'
            - '.gif'
            - '.jpeg'
            - '.jpg'
            - '.jsp'
            - '.jspx'
            - '.log'
            - '.png'
            - '.ps1'
            - '.psm1'
            - '.rar'
            - '.scf'
            - '.sct'
            - '.txt'
            - '.vbe'
            - '.vbs'
            - '.war'
            - '.wsf'
            - '.wsh'
            - '.xll'
            - '.zip'
    condition: all of selection_*
falsepositives:
    - Unknown
level: high
regression_tests_path: regression_data/rules/windows/process_creation/proc_creation_win_bitsadmin_download_susp_extensions/info.yml
simulation:
    - type: atomic-red-team
      name: Windows - BITSAdmin BITS Download
      technique: T1105
      atomic_guid: a1921cd3-9a2d-47d5-a891-f1d0f2a7a31b

Original YAML and metadata in JSON

False positives

• Unknown

Source references

• https://blog.netspi.com/15-ways-to-download-a-file/#bitsadmin
• https://isc.sans.edu/diary/22264
• https://lolbas-project.github.io/lolbas/Binaries/Bitsadmin/