Windows Renamed Command Interpreter was Executed

 Original Source: [splunk source]
Name:Windows Renamed Command Interpreter was Executed
id:6f4611be-076e-4fa8-bc78-466588a71442
version:1
date:None
author:Onur Mustafa Erdogan, Splunk
status:production
type:Anomaly
Description:The following analytic identifies a Windows command interpreter process being executed where it's process name does not match it's original file name attribute. Processes that have been renamed and executed may be an indicator that an adversary is attempting to evade defenses or execute malicious code.
Data_source:
  • -Sysmon EventID 1
  • -CrowdStrike ProcessRollup2
search:| tstats `security_content_summariesonly`
count min(_time) AS firstTime
max(_time) AS lastTime

FROM datamodel=Endpoint.Processes WHERE

[

| inputlookup renamed_windows_command_interpreter_binaries

| rename original_file_name as Processes.original_file_name

| table Processes.original_file_name
]

by Processes.action Processes.dest Processes.original_file_name Processes.parent_process
Processes.parent_process_exec Processes.parent_process_guid Processes.parent_process_id
Processes.parent_process_name Processes.parent_process_path
Processes.process Processes.process_exec Processes.process_guid
Processes.process_hash Processes.process_id Processes.process_integrity_level
Processes.process_name Processes.process_path
Processes.user Processes.user_id Processes.vendor_product

| `drop_dm_object_name(Processes)`

| eval process_name_norm=replace(lower(process_name), "\.exe$", ""),
original_file_name_norm=replace(lower(original_file_name), "\.exe$", "")
| where process_name_norm != original_file_name_norm

| lookup local=t renamed_windows_command_interpreter_binaries original_file_name OUTPUT description

| `security_content_ctime(firstTime)`
| `security_content_ctime(lastTime)`
| `windows_renamed_command_interpreter_was_executed_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:3rd party software binaries sharing the same name as Windows command interpreter binaries may trigger false positives.
References:
  -https://attack.mitre.org/techniques/T1036/
  -https://attack.mitre.org/techniques/T1036/003/
  -https://attack.mitre.org/techniques/T1059/
  -https://redcanary.com/threat-detection-report/techniques/rename-system-utilities/
drilldown_searches:
 name:'View the detection results for - "$dest$" and "$user$"'
 search:'%original_detection_search% | search dest = "$dest$" user = "$user$"'
 earliest_offset:'$info_min_time$'
 latest_offset:'$info_max_time$'
 name:'View risk events for the last 7 days for - "$dest$" and "$user$"'
 search:'| from datamodel Risk.All_Risk | search normalized_risk_object IN ("$dest$", "$user$") | stats count min(_time) as firstTime max(_time) as lastTime values(search_name) as "Search Name" values(risk_message) as "Risk Message" values(analyticstories) as "Analytic Stories" values(annotations._all) as "Annotations" values(annotations.mitre_attack.mitre_tactic) as "ATT&CK Tactics" by normalized_risk_object | `security_content_ctime(firstTime)` | `security_content_ctime(lastTime)`'
 earliest_offset:'7d'
 latest_offset:'0'
analytic_story:['Living Off The Land', 'Masquerading - Rename System Utilities', 'Suspicious Command-Line Executions', 'Windows Defense Evasion Tactics', 'Water Gamayun']

asset_type:Endpoint

mitre_attack_id:['T1036.003', 'T1059']

product:['Splunk Enterprise', 'Splunk Enterprise Security', 'Splunk Cloud']

category:endpoint

security_domain:endpoint

tags:

tests:
 name:'True Positive Test'
 attack_data:
  data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1036.003/renamed_command_interpreter/renamed_command_interpreter.log
  source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
  sourcetype: XmlWinEventLog
 test_type:'unit'
manual_test:None