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splunk-security_content/detections/endpoint/detect_mshta_inline_hta_execution.yml
2023-09-15 10:58:38 -07:00

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YAML

name: Detect mshta inline hta execution
id: a0873b32-5b68-11eb-ae93-0242ac130002
version: 6
date: '2021-09-16'
author: Bhavin Patel, Michael Haag, Splunk
status: production
type: TTP
description: The following analytic identifies "mshta.exe" execution with inline protocol
handlers. "JavaScript", "VBScript", and "About" are the only supported options when
invoking HTA content directly on the command-line. The search will return the first
time and last time these command-line arguments were used for these executions,
as well as the target system, the user, process "mshta.exe" and its parent process.
data_source:
- Sysmon Event ID 1
search: '| tstats `security_content_summariesonly` count values(Processes.process)
as process values(Processes.parent_process) as parent_process min(_time) as firstTime
max(_time) as lastTime from datamodel=Endpoint.Processes where `process_mshta` (Processes.process=*vbscript*
OR Processes.process=*javascript* OR Processes.process=*about*) by Processes.user
Processes.process_name Processes.original_file_name Processes.parent_process_name
Processes.dest | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)`|
`security_content_ctime(lastTime)` | `detect_mshta_inline_hta_execution_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: Although unlikely, some legitimate applications may exhibit
this behavior, triggering a false positive.
references:
- https://github.com/redcanaryco/AtomicTestHarnesses
- https://redcanary.com/blog/introducing-atomictestharnesses/
- https://docs.microsoft.com/en-us/windows/win32/search/-search-3x-wds-extidx-prot-implementing
tags:
analytic_story:
- Suspicious MSHTA Activity
- Living Off The Land
asset_type: Endpoint
confidence: 100
impact: 90
message: An instance of $parent_process_name$ spawning $process_name$ was identified
on endpoint $dest$ by user $user$ executing with inline HTA, indicative of defense
evasion.
mitre_attack_id:
- T1218
- T1218.005
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: 90
security_domain: endpoint
tests:
- name: True Positive Test
attack_data:
- data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1218.005/atomic_red_team/windows-sysmon.log
source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
sourcetype: xmlwineventlog