name: PowerShell Start-BitsTransfer
id: 39e2605a-90d8-11eb-899e-acde48001122
version: 2
date: '2021-03-29'
author: Michael Haag, Splunk
type: TTP
datamodel:
- Endpoint
description: Start-BitsTransfer is the PowerShell "version" of BitsAdmin.exe. Similar
  functionality is present. This technique variation is not as commonly used by adversaries,
  but has been abused in the past. Lesser known uses include the ability to set the
  `-TransferType` to `Upload` for exfiltration of files. In an instance where `Upload`
  is used, it is highly possible files will be archived. During triage, review parallel
  processes and process lineage. Capture any files on disk and review. For the remote
  domain or IP, what is the reputation?
search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time)
  as lastTime from datamodel=Endpoint.Processes where `process_powershell` Processes.process=*start-bitstransfer*
  by Processes.dest Processes.user Processes.parent_process Processes.process_name
  Processes.process Processes.process_id Processes.original_file_name Processes.parent_process_id
  | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`
  | `powershell_start_bitstransfer_filter`'
how_to_implement: To successfully implement this search you need to be ingesting information
  on process that include the name of the process responsible for the changes from
  your endpoints into the `Endpoint` datamodel in the `Processes` node. In addition,
  confirm the latest CIM App 4.20 or higher is installed and the latest TA for the
  endpoint product.
known_false_positives: Limited false positives. It is possible administrators will
  utilize Start-BitsTransfer for administrative tasks, otherwise filter based parent
  process or command-line arguments.
references:
- https://isc.sans.edu/diary/Investigating+Microsoft+BITS+Activity/23281
- https://docs.microsoft.com/en-us/windows/win32/bits/using-windows-powershell-to-create-bits-transfer-jobs
tags:
  analytic_story:
  - BITS Jobs
  confidence: 80
  context:
  - Source:Endpoint
  - Stage:Defense Evasion
  dataset:
  - https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1197/atomic_red_team/windows-sysmon.log
  impact: 70
  kill_chain_phases:
  - Exploitation
  message: A suspicious process $process_name$ with commandline $process$ that are
    related to bittransfer functionality in host $dest$
  mitre_attack_id:
  - T1197
  observable:
  - name: dest
    type: Hostname
    role:
    - Victim
  - name: user
    type: User
    role:
    - Victim
  product:
  - Splunk Enterprise
  - Splunk Enterprise Security
  - Splunk Cloud
  required_fields:
  - _time
  - Processes.dest
  - Processes.user
  - Processes.parent_process_name
  - Processes.parent_process
  - Processes.original_file_name
  - Processes.process_name
  - Processes.process
  - Processes.process_id
  - Processes.parent_process_path
  - Processes.process_path
  - Processes.parent_process_id
  risk_score: 56
  security_domain: endpoint
  supported_tas:
  - Splunk_TA_microsoft_sysmon
  asset_type: Endpoint