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patel-bhavin
94 lines
3.7 KiB
YAML
94 lines
3.7 KiB
YAML
name: Windows PowerShell Start-BitsTransfer
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id: 0bafd086-8f61-11ec-996e-acde48001122
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version: 1
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date: '2022-02-16'
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author: Michael Haag, Splunk
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type: TTP
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datamodel:
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- Endpoint_Processes
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description: Start-BitsTransfer is the PowerShell "version" of BitsAdmin.exe. Similar
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functionality is present. This technique variation is not as commonly used by adversaries,
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but has been abused in the past. Lesser known uses include the ability to set the
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`-TransferType` to `Upload` for exfiltration of files. In an instance where `Upload`
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is used, it is highly possible files will be archived. During triage, review parallel
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processes and process lineage. Capture any files on disk and review. For the remote
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domain or IP, what is the reputation?
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search: '| from read_ssa_enriched_events() | eval timestamp=parse_long(ucast(map_get(input_event,
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"_time"), "string", null)), cmd_line=lower(ucast(map_get(input_event, "process"),
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"string", null)), process_name=lower(ucast(map_get(input_event, "process_name"),
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"string", null)), process_path=ucast(map_get(input_event, "process_path"), "string",
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null), parent_process_name=ucast(map_get(input_event, "parent_process_name"), "string",
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null), event_id=ucast(map_get(input_event, "event_id"), "string", null) | where
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cmd_line IS NOT NULL AND process_name IS NOT NULL | where process_name="pwsh.exe"
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OR process_name="pwsh.exe" OR process_name="sqlps.exe" OR process_name="sqltoolsps.exe"
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OR process_name="powershell.exe" OR process_name="powershell_ise.exe" | where (like
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(cmd_line, "%start-bitstransfer%")) | eval start_time=timestamp, end_time=timestamp,
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entities=mvappend(ucast(map_get(input_event, "dest_user_id"), "string", null), ucast(map_get(input_event,
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"dest_device_id"), "string", null)), body=create_map(["event_id", event_id, "cmd_line",
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cmd_line, "process_name", process_name, "parent_process_name", parent_process_name,
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"process_path", process_path]) | into write_ssa_detected_events();'
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how_to_implement: To successfully implement this search you need to be ingesting information
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on process that include the name of the process responsible for the changes from
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your endpoints into the `Endpoint_Processess` datamodel.
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known_false_positives: Limited false positives. It is possible administrators will
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utilize Start-BitsTransfer for administrative tasks, otherwise filter based parent
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process or command-line arguments.
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references:
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- https://isc.sans.edu/diary/Investigating+Microsoft+BITS+Activity/23281
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- https://docs.microsoft.com/en-us/windows/win32/bits/using-windows-powershell-to-create-bits-transfer-jobs
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tags:
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analytic_story:
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- BITS Jobs
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- Living Off The Land
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automated_detection_testing: passed
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cis20:
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- CIS 8
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nist:
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- PR.PT
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- DE.CM
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confidence: 70
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context:
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- Source:Endpoint
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- Stage:Exfiltration
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dataset:
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- https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1197/atomic_red_team/T1197_windows-security.log
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impact: 70
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kill_chain_phases:
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- Exploitation
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message: An instance of $parent_process_name$ spawning $process_name$ was identified
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on endpoint $dest$ by user $dest_user_id$ attempting to download a file.
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mitre_attack_id:
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- T1197
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- T1105
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observable:
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- name: dest_user_id
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type: User
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role:
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- Victim
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- name: dest_device_id
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type: Hostname
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role:
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- Victim
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- name: parent_process_name
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type: Process
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role:
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- Parent Process
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- name: process_name
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type: Process
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role:
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- Child Process
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product:
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- Splunk Behavioral Analytics
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required_fields:
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- _time
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- dest_device_id
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- process_name
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- parent_process_name
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- process_path
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- dest_user_id
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- process
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- cmd_line
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risk_score: 49
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security_domain: endpoint
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asset_type: Endpoint
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