Persistence via Microsoft Office AddIns

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Detects attempts to establish persistence on an endpoint by abusing Microsoft Office add-ins.

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
  • Persistence

Version: 4

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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file where event.type != "deletion" and
 file.extension : ("wll","xll","ppa","ppam","xla","xlam") and
 file.path :
    (
    "C:\\Users\\*\\AppData\\Roaming\\Microsoft\\Word\\Startup\\*",
    "C:\\Users\\*\\AppData\\Roaming\\Microsoft\\AddIns\\*",
    "C:\\Users\\*\\AppData\\Roaming\\Microsoft\\Excel\\XLSTART\\*"
    )

Framework: MITRE ATT&CKTM