Suspicious Process Execution via Renamed PsExec Executable

edit

Suspicious Process Execution via Renamed PsExec Executable

edit

Identifies suspicious psexec activity which is executing from the psexec service that has been renamed, possibly to evade detection.

Rule type: eql

Rule indices:

  • winlogbeat-*
  • logs-endpoint.events.*
  • logs-windows.*

Severity: medium

Risk score: 47

Runs every: 5 minutes

Searches indices from: now-9m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

Tags:

  • Elastic
  • Host
  • Windows
  • Threat Detection
  • Execution

Version: 5 (version history)

Added (Elastic Stack release): 7.10.0

Last modified (Elastic Stack release): 8.2.0

Rule authors: Elastic

Rule license: Elastic License v2

Investigation guide

edit
## Config

If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define `event.ingested` and default fallback for EQL rules was not added until 8.2, so you will need to add a custom pipeline to populate `event.ingested` to @timestamp for this rule to work.

Rule query

edit
process where event.type in ("start", "process_started", "info") and
process.pe.original_file_name : "psexesvc.exe" and not process.name :
"PSEXESVC.exe"

Threat mapping

edit

Framework: MITRE ATT&CKTM

Rule version history

edit
Version 5 (8.2.0 release)
  • Formatting only
Version 4 (7.12.0 release)
  • Formatting only
Version 3 (7.11.2 release)
  • Formatting only
Version 2 (7.11.0 release)
  • Updated query, changed from:

    event.category:process and event.type:(start or process_started) and
    (process.pe.original_file_name:(psexesvc.exe or PSEXESVC.exe) or
    winlog.event_data.OriginalFileName:(psexesvc.exe or PSEXESVC.exe)) and
    process.parent.name:services.exe and not process.name:(psexesvc.exe or
    PSEXESVC.exe)