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splunk-security_content/dev/endpoint/suspicious_microsoft_workflow_compiler_rename.yml
2023-01-20 13:24:15 +01:00

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2.5 KiB
YAML

name: Suspicious microsoft workflow compiler rename
id: f0db4464-55d9-11eb-ae93-0242ac130002
version: 4
date: '2022-04-07'
author: Michael Haag, Splunk
status: production
type: Hunting
description: The following analytic identifies a renamed instance of microsoft.workflow.compiler.exe.
Microsoft.workflow.compiler.exe is natively found in C:\Windows\Microsoft.NET\Framework64\v4.0.30319
and is rarely utilized. When investigating, identify the executed code on disk and
review. A spawned child process from microsoft.workflow.compiler.exe is uncommon.
In any instance, microsoft.workflow.compiler.exe spawning from an Office product
or any living off the land binary is highly suspect.
data_source:
- Sysmon Event ID 1
search:
selection1:
OriginalFileName: Microsoft.Workflow.Compiler.exe
Image|endswith: microsoft.workflow.compiler.exe
condition: selection1
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: Although unlikely, some legitimate applications may use a moved
copy of microsoft.workflow.compiler.exe, triggering a false positive.
references:
- https://lolbas-project.github.io/lolbas/Binaries/Microsoft.Workflow.Compiler/
- https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1218/T1218.md#atomic-test-6---microsoftworkflowcompilerexe-payload-execution
tags:
analytic_story:
- Trusted Developer Utilities Proxy Execution
- Cobalt Strike
- Masquerading - Rename System Utilities
- Living Off The Land
asset_type: Endpoint
confidence: 90
impact: 70
message: Suspicious renamed microsoft.workflow.compiler.exe binary ran on $dest$
by $user$
mitre_attack_id:
- T1036
- T1127
- T1036.003
observable:
- name: dest
type: Endpoint
role:
- Victim
- name: User
type: User
role:
- Victim
product:
- Splunk Enterprise
- Splunk Enterprise Security
- Splunk Cloud
risk_score: 63
security_domain: endpoint
tests:
- name: True Positive Test
attack_data:
- data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1127/atomic_red_team/windows-sysmon.log
source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
sourcetype: xmlwineventlog