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splunk-security_content/detections/endpoint/msbuild_suspicious_spawned_by_script_process.yml

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YAML

name: MSBuild Suspicious Spawned By Script Process
id: 213b3148-24ea-11ec-93a2-acde48001122
version: 1
date: '2021-10-04'
author: Teoderick Contreras, Splunk
type: TTP
datamodel:
- Endpoint
description: This analytic is to detect a suspicious child process of MSBuild spawned
by Windows Script Host - cscript or wscript. This behavior or event are commonly
seen and used by malware or adversaries to execute malicious msbuild process using
malicious script in the compromised host. During triage, review parallel processes
and identify any file modifications. MSBuild may load a script from the same path
without having command-line arguments.
search: '| tstats `security_content_summariesonly` count values(Processes.process_name)
as process_name values(Processes.process) as process min(_time) as firstTime max(_time)
as lastTime from datamodel=Endpoint.Processes where Processes.parent_process_name
IN ("wscript.exe", "cscript.exe") AND `process_msbuild` by Processes.dest Processes.parent_process
Processes.parent_process_name Processes.process_name Processes.original_file_name
Processes.user | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)` | `msbuild_suspicious_spawned_by_script_process_filter`'
how_to_implement: To successfully implement this search you need to be ingesting information
on process that include the name of the process responsible for the changes from
your endpoints into the `Endpoint` datamodel in the `Processes` node. In addition,
confirm the latest CIM App 4.20 or higher is installed and the latest TA for the
endpoint product.
known_false_positives: False positives should be limited as developers do not spawn
MSBuild via a WSH.
references:
- https://app.any.run/tasks/dc93ee63-050c-4ff8-b07e-8277af9ab939/
tags:
analytic_story:
- Trusted Developer Utilities Proxy Execution MSBuild
confidence: 70
context:
- Stage:Execution
- Stage:Defense Evasion
dataset:
- https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1127.001/regsvr32_silent/sysmon.log
impact: 70
kill_chain_phases:
- Exploitation
message: Msbuild.exe process spawned by $parent_process_name$ on $dest$ executed
by $user$
mitre_attack_id:
- T1127.001
- T1127
observable:
- name: dest
type: Endpoint
role:
- Victim
- name: User
type: User
role:
- Victim
product:
- Splunk Enterprise
- Splunk Enterprise Security
- Splunk Cloud
required_fields:
- _time
- Processes.dest
- Processes.parent_process
- Processes.parent_process_name
- Processes.process_name
- Processes.original_file_name
- Processes.user
risk_score: 49
security_domain: endpoint
supported_tas:
- Splunk_TA_microsoft_sysmon
asset_type: Endpoint