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Elastic Docs ›Elastic Security Solution [7.16] ›Detections and alerts ›Prebuilt rule reference

Creation of Hidden Files and Directories

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Creation of Hidden Files and Directories

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Users can mark specific files as hidden simply by putting a "." as the first character in the file or folder name. Adversaries can use this to their advantage to hide files and folders on the system for persistence and defense evasion. This rule looks for hidden files or folders in common writable directories.

Rule type: eql

Rule indices:

  • auditbeat-*
  • logs-endpoint.events.*

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: 33

Tags:

  • Elastic
  • Host
  • Linux
  • Threat Detection
  • Defense Evasion

Version: 7 (version history)

Added (Elastic Stack release): 7.9.0

Last modified (Elastic Stack release): 7.14.0

Rule authors: Elastic

Rule license: Elastic License v2

Potential false positives

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Certain tools may create hidden temporary files or directories upon installation or as part of their normal behavior. These events can be filtered by the process arguments, username, or process name values.

Rule query

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process where event.type in ("start", "process_started") and
process.working_directory in ("/tmp", "/var/tmp", "/dev/shm") and
process.args regex~ """\.[a-z0-9_\-][a-z0-9_\-\.]{1,254}""" and not
process.name in ("ls", "find")

Threat mapping

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Framework: MITRE ATT&CKTM

Rule version history

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Version 7 (7.14.0 release)

  • Updated query, changed from:

    event.category:process AND event.type:(start or process_started) AND
process.working_directory:("/tmp" or "/var/tmp" or "/dev/shm") AND
process.args:/\.[a-zA-Z0-9_\-][a-zA-Z0-9_\-\.]{1,254}/ AND NOT
process.name:(ls or find)
Version 6 (7.12.0 release)
  • Formatting only
Version 5 (7.11.2 release)
  • Formatting only
Version 4 (7.11.0 release)
  • Formatting only
Version 3 (7.10.0 release)
  • Formatting only
Version 2 (7.9.1 release)
  • Formatting only
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