Detection rules › Splunk

Detect Renamed PSExec

Status
production
Group by
IntegrityLevel, command_line, computer_name, event_action, original_file_name, parent_command_line, parent_process_guid, parent_process_id, parent_process_name, process_guid, process_hash, process_id, process_name, user, user_id, vendor_product
Author
Michael Haag, Splunk, Alex Oberkircher, Github Community
Source
github.com/splunk/security_content

The following analytic identifies instances where PsExec.exe has been renamed and executed on an endpoint. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process names and original file names. This activity is significant because renaming PsExec.exe is a common tactic to evade detection. If confirmed malicious, this could allow an attacker to execute commands remotely, potentially leading to unauthorized access, lateral movement, or further compromise of the network.

MITRE ATT&CK coverage

Event coverage

Rule body splunk

name: Detect Renamed PSExec
id: 683e6196-b8e8-11eb-9a79-acde48001122
version: 17
creation_date: '2021-06-03'
modification_date: '2026-05-13'
author: Michael Haag, Splunk, Alex Oberkircher, Github Community
status: production
type: Hunting
description: The following analytic identifies instances where `PsExec.exe` has been renamed and executed on an endpoint. It leverages data from Endpoint Detection and Response (EDR) agents, focusing on process names and original file names. This activity is significant because renaming `PsExec.exe` is a common tactic to evade detection. If confirmed malicious, this could allow an attacker to execute commands remotely, potentially leading to unauthorized access, lateral movement, or further compromise of the network.
data_source:
    - Sysmon EventID 1
    - Windows Event Log Security 4688
    - CrowdStrike ProcessRollup2
search: |-
    | tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes
      WHERE (
            Processes.process_name!=psexec.exe
            AND
            Processes.process_name!=psexec64.exe
        )
        AND Processes.original_file_name=psexec.c
      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)`
    | `security_content_ctime(firstTime)`
    | `security_content_ctime(lastTime)`
    | `detect_renamed_psexec_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: Limited false positives should be present. It is possible some third party applications may use older versions of PsExec, filter as needed.
references:
    - https://github.com/redcanaryco/atomic-red-team/blob/master/atomics/T1569.002/T1569.002.yaml
    - https://redcanary.com/blog/threat-hunting-psexec-lateral-movement/
analytic_story:
    - Active Directory Lateral Movement
    - BlackByte Ransomware
    - Cactus Ransomware
    - China-Nexus Threat Activity
    - CISA AA22-320A
    - DarkGate Malware
    - DarkSide Ransomware
    - DHS Report TA18-074A
    - HAFNIUM Group
    - Medusa Ransomware
    - Rhysida Ransomware
    - Salt Typhoon
    - SamSam Ransomware
    - Sandworm Tools
    - VanHelsing Ransomware
asset_type: Endpoint
mitre_attack_id:
    - T1569.002
product:
    - Splunk Enterprise
    - Splunk Enterprise Security
    - Splunk Cloud
category: endpoint
security_domain: endpoint
tests:
    - name: True Positive Test
      attack_data:
        - data: https://media.githubusercontent.com/media/splunk/attack_data/master/datasets/attack_techniques/T1569.002/atomic_red_team/windows-sysmon.log
          source: XmlWinEventLog:Microsoft-Windows-Sysmon/Operational
          sourcetype: XmlWinEventLog
      test_type: unit

Stages and Predicates

Stage 1: tstats

| tstats `security_content_summariesonly` count min(_time) as firstTime max(_time) as lastTime FROM datamodel=Endpoint.Processes
  WHERE (
        Processes.process_name!=psexec.exe
        AND
        Processes.process_name!=psexec64.exe
    )
    AND Processes.original_file_name=psexec.c
  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

Stage 2: search

| `drop_dm_object_name(Processes)`

Stage 3: search

| `security_content_ctime(firstTime)`

Stage 4: search

| `security_content_ctime(lastTime)`

Stage 5: search

| `detect_renamed_psexec_filter`

Indicators

Each row is a field, operator, and value that the rule matches. The corpus column counts how many other rules in the catalog look for the same combination: high numbers point to widely-used, community-vetted indicators. Blank or 1 shows that the indicator is specific to this rule.

FieldKindValues
Processes.original_file_nameeq
  • "psexec.c" corpus 6 (sigma 2, elastic 2, splunk 2)
Processes.process_namene
  • psexec.exe
  • psexec64.exe