windows_phishing_pdf_file_executes_url_link.yml

name: Windows Phishing PDF File Executes URL Link
id: 2fa9dec8-9d8e-46d3-96c1-202c06f0e6e1
version: 1
date: '2023-01-18'
author: Teoderick Contreras, Splunk
status: production
type: Anomaly
description: This analytic is developed to detect suspicious pdf viewer processes
  that have a browser application child processes. This event was seen in a pdf spear
  phishing attachment containing a malicious URL link to download the actual payload.
  When a user clicks the malicious link the pdf viewer application will execute a
  process of the host default browser to connect to the malicious site. This anomaly
  detection can be a good indicator that a possible pdf file has a link executed by
  a user. The pdf viewer and browser list in this detection is still in progress,
  add the common browser and pdf viewer you use in opening pdf in your network.
data_source:
- Sysmon EventID 1
search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time)
  as lastTime from datamodel=Endpoint.Processes where Processes.parent_process_name  IN
  ("AcroRd32.exe", "FoxitPDFReader.exe") Processes.process_name IN ("firefox.exe",
  "chrome.exe", "iexplore.exe") by Processes.user Processes.parent_process_name Processes.process_name  Processes.parent_process
  Processes.process Processes.process_id Processes.dest |`drop_dm_object_name(Processes)`
  | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)` | `windows_phishing_pdf_file_executes_url_link_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: False positives in PDF file opened PDF Viewer having legitimate
  URL link, however filter as needed.
references:
- https://twitter.com/pr0xylife/status/1615382907446767616?s=20
tags:
  analytic_story:
  - Spearphishing Attachments
  - Snake Keylogger
  asset_type: Endpoint
  confidence: 80
  impact: 80
  message: a pdf file opened in pdf viewer process $parent_process_name$ has a child
    process of a browser $process_name$ in $dest$
  mitre_attack_id:
  - T1566.001
  - T1566
  observable:
  - name: dest
    type: Hostname
    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: 64
  security_domain: endpoint
tests:
- name: True Positive Test
  attack_data:
  - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1566.001/phishing_pdf_uri/sysmon.log
    source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
    sourcetype: xmlwineventlog
    update_timestamp: true