IMPORTANT: No additional bug fixes or documentation updates will be released for this version. For the latest information, see the current release documentation.
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Elastic Docs ›Elastic Security Solution [7.16] ›Downloadable rule update v0.16.2

Microsoft Exchange Worker Spawning Suspicious Processes

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Microsoft Exchange Worker Spawning Suspicious Processes

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Identifies suspicious processes being spawned by the Microsoft Exchange Server worker process (w3wp). This activity may indicate exploitation activity or access to an existing web shell backdoor.

Rule type: eql

Rule indices:

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

Severity: high

Risk score: 73

Runs every: 5m

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

Maximum alerts per execution: 100

References:

Tags:

  • Elastic
  • Host
  • Windows
  • Threat Detection
  • Initial Access

Version: 3

Rule authors:

  • Elastic

Rule license: Elastic License v2

Investigation guide

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## 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

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process where event.type == "start" and
  process.parent.name : "w3wp.exe" and process.parent.args : "MSExchange*AppPool" and
  (process.name : ("cmd.exe", "powershell.exe", "pwsh.exe", "powershell_ise.exe") or
  process.pe.original_file_name in ("cmd.exe", "powershell.exe", "pwsh.dll", "powershell_ise.exe"))

Framework: MITRE ATT&CKTM

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