name: PowerShell Start-BitsTransfer
id: 39e2605a-90d8-11eb-899e-acde48001122
version: 2
date: '2021-03-29'
author: Michael Haag, Splunk
status: production
type: TTP
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?
data_source:
- Sysmon Event ID 1
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: The detection is based on data that originates from Endpoint Detection
  and Response (EDR) agents. These agents are designed to provide security-related
  telemetry from the endpoints where the agent is installed. To implement this search,
  you must ingest logs that contain the process GUID, process name, and parent process.
  Additionally, you must ingest complete command-line executions. These logs must
  be processed using the appropriate Splunk Technology Add-ons that are specific to
  the EDR product. The logs must also be mapped to the `Processes` node of the `Endpoint`
  data model. Use the Splunk Common Information Model (CIM) to normalize the field
  names and speed up the data modeling process.
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
  asset_type: Endpoint
  confidence: 80
  impact: 70
  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
tests:
- name: True Positive Test
  attack_data:
  - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1197/atomic_red_team/windows-sysmon.log
    source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
    sourcetype: xmlwineventlog