windows_curl_download_to_suspicious_path.yml

name: Windows Curl Download to Suspicious Path
id: c32f091e-30db-11ec-8738-acde48001122
version: 1
date: '2021-10-19'
author: Michael Haag, Splunk
status: production
type: TTP
description: 'The following analytic identifies the use of Windows Curl.exe downloading
  a file to a suspicious location. 

  -O or --output is used when a file is to be downloaded and placed in a specified
  location. 

  During triage, review parallel processes for further behavior. In addition, identify
  if the download was successful. If a file was downloaded, capture and analyze.'
data_source:
- Sysmon EventID 1
search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time)
  as lastTime from datamodel=Endpoint.Processes where `process_curl` Processes.process
  IN ("*-O *","*--output*") Processes.process IN ("*\\appdata\\*","*\\programdata\\*","*\\public\\*")
  by Processes.dest Processes.user Processes.parent_process_name Processes.process_name
  Processes.original_file_name Processes.process Processes.process_id Processes.parent_process_id
  | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`
  | `windows_curl_download_to_suspicious_path_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: It is possible Administrators or super users will use Curl
  for legitimate purposes. Filter as needed.
references:
- https://thedfirreport.com/2021/10/18/icedid-to-xinglocker-ransomware-in-24-hours/
- https://attack.mitre.org/techniques/T1105/
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1105/T1105.md
tags:
  analytic_story:
  - IcedID
  - Ingress Tool Transfer
  - Forest Blizzard
  asset_type: Endpoint
  confidence: 100
  impact: 80
  message: An instance of $parent_process_name$ spawning $process_name$ was identified
    on endpoint $dest$ by user $user$ to download a file to a suspicious directory.
  mitre_attack_id:
  - T1105
  observable:
  - name: user
    type: User
    role:
    - Victim
  - name: dest
    type: Hostname
    role:
    - Victim
  - name: parent_process_name
    type: Process
    role:
    - Parent Process
  - name: process_name
    type: Process
    role:
    - Child Process
  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: 80
  security_domain: endpoint
tests:
- name: True Positive Test
  attack_data:
  - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1105/atomic_red_team/windows-sysmon_curl.log
    source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
    sourcetype: xmlwineventlog