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winword_spawning_powershell.yml
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winword_spawning_powershell.yml
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name: Winword Spawning PowerShell
id: b2c950b8-9be2-11eb-8658-acde48001122
version: 4
date: '2024-08-14'
author: Michael Haag, Splunk
status: production
type: TTP
description: The following analytic identifies instances where Microsoft Word (winword.exe)
spawns a PowerShell process. This behavior is detected using Endpoint Detection
and Response (EDR) telemetry, focusing on process creation events where the parent
process is winword.exe. This activity is significant because it is uncommon and
often associated with spearphishing attacks, where malicious documents execute encoded
PowerShell commands. If confirmed malicious, this could allow an attacker to execute
arbitrary code, potentially leading to data exfiltration, system compromise, or
further lateral movement within the network.
data_source:
- Sysmon EventID 1
- Windows Event Log Security 4688
- CrowdStrike ProcessRollup2
search: '| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time)
as lastTime from datamodel=Endpoint.Processes where Processes.parent_process_name="winword.exe"
`process_powershell` by Processes.dest Processes.user Processes.parent_process_name
Processes.parent_process 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)` | `winword_spawning_powershell_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 should be limited, but if any are present,
filter as needed.
references:
- https://redcanary.com/threat-detection-report/techniques/powershell/
- https://attack.mitre.org/techniques/T1566/001/
- https://app.any.run/tasks/b79fa381-f35c-4b3e-8d02-507e7ee7342f/
- https://app.any.run/tasks/181ac90b-0898-4631-8701-b778a30610ad/
tags:
analytic_story:
- Spearphishing Attachments
- DarkCrystal RAT
- CVE-2023-21716 Word RTF Heap Corruption
asset_type: Endpoint
confidence: 100
impact: 70
message: '$parent_process_name$ on $dest$ by $user$ launched the following powershell
process: $process_name$ which is very common in spearphishing attacks'
mitre_attack_id:
- T1566
- T1566.001
observable:
- name: dest
type: Endpoint
role:
- Victim
- name: user
type: User
role:
- Victim
- name: process_name
type: Process
role:
- Attacker
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: 70
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/macro/windows-sysmon.log
source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
sourcetype: xmlwineventlog