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splunk-security_content/detections/endpoint/suspicious_msbuild_spawn.yml

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YAML

name: Suspicious MSBuild Spawn
id: a115fba6-5514-11eb-ae93-0242ac130002
version: 2
date: '2021-01-12'
author: Michael Haag, Splunk
status: production
type: TTP
description: The following analytic identifies wmiprvse.exe spawning msbuild.exe.
This behavior is indicative of a COM object being utilized to spawn msbuild from
wmiprvse.exe. It is common for MSBuild.exe to be spawned from devenv.exe while using
Visual Studio. In this instance, there will be command line arguments and file paths.
In a malicious instance, MSBuild.exe will spawn from non-standard processes and
have no command line arguments. For example, MSBuild.exe spawning from explorer.exe,
powershell.exe is far less common and should be investigated.
data_source:
- Sysmon Event ID 1
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=wmiprvse.exe
AND `process_msbuild` by Processes.dest Processes.parent_process Processes.original_file_name
Processes.user | `drop_dm_object_name(Processes)` | `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)` | `suspicious_msbuild_spawn_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://lolbas-project.github.io/lolbas/Binaries/Msbuild/
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1127.001/T1127.001.md
tags:
analytic_story:
- Trusted Developer Utilities Proxy Execution MSBuild
- Living Off The Land
asset_type: Endpoint
confidence: 60
impact: 70
message: Suspicious msbuild.exe process executed on $dest$ by $user$
mitre_attack_id:
- T1127
- T1127.001
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.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: 42
security_domain: endpoint
tests:
- name: True Positive Test
attack_data:
- data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1127.001/windows-sysmon.log
source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
sourcetype: xmlwineventlog
update_timestamp: true