AWS EFS File System or Mount Deleted

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Detects when an EFS File System or Mount is deleted. An adversary could break any file system using the mount target that is being deleted, which might disrupt instances or applications using those mounts. The mount must be deleted prior to deleting the File System, or the adversary will be unable to delete the File System.

Rule type: query

Rule indices:

  • filebeat-*
  • logs-aws*

Severity: medium

Risk score: 47

Runs every: 10 minutes

Searches indices from: now-60m (Date Math format, see also Additional look-back time)

Maximum alerts per execution: 100

References:

Tags:

  • Elastic
  • Cloud
  • AWS
  • Continuous Monitoring
  • SecOps
  • Data Protection

Version: 5 (version history)

Added (Elastic Stack release): 7.16.0

Last modified (Elastic Stack release): 8.4.0

Rule authors: Austin Songer

Rule license: Elastic License v2

Potential false positives

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File System or Mount being deleted may be performed by a system administrator. Verify whether the user identity, user agent, and/or hostname should be making changes in your environment. File System Mount deletion by unfamiliar users should be investigated. If known behavior is causing false positives, it can be exempted from the rule.

Investigation guide

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Rule query

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event.dataset:aws.cloudtrail and
event.provider:elasticfilesystem.amazonaws.com and
event.action:(DeleteMountTarget or DeleteFileSystem) and
event.outcome:success

Threat mapping

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Framework: MITRE ATT&CKTM

Rule version history

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Version 5 (8.4.0 release)
  • Updated query, changed from:

    event.dataset:aws.cloudtrail and
    event.provider:elasticfilesystem.amazonaws.com and
    event.action:(DeleteMountTarget or DeleteFileSystem) and
    event.outcome:success
Version 3 (8.2.0 release)
  • Formatting only
Version 2 (8.1.0 release)
  • Formatting only