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Elastic Docs ›Elastic Security Solution [8.8] ›Detections and alerts ›Prebuilt rule reference

Suspicious Calendar File Modification

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Suspicious Calendar File Modification

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Identifies suspicious modifications of the calendar file by an unusual process. Adversaries may create a custom calendar notification procedure to execute a malicious program at a recurring interval to establish persistence.

Rule type: query

Rule indices:

  • logs-endpoint.events.*

Severity: medium

Risk score: 47

Runs every: 5m

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

Maximum alerts per execution: 100

References:

Tags:

  • Domain: Endpoint
  • OS: macOS
  • Use Case: Threat Detection
  • Tactic: Persistence
  • Data Source: Elastic Defend

Version: 105

Rule authors:

  • Elastic

Rule license: Elastic License v2

Rule query

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event.category:file and host.os.type:macos and event.action:modification and
  file.path:/Users/*/Library/Calendars/*.calendar/Events/*.ics and
  process.executable:
  (* and not
    (
      /System/Library/* or
      /System/Applications/Calendar.app/Contents/MacOS/* or
      /System/Applications/Mail.app/Contents/MacOS/Mail or
      /usr/libexec/xpcproxy or
      /sbin/launchd or
      /Applications/*
    )
  )

Framework: MITRE ATT&CKTM

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