AWS EC2 Network Access Control List Creation

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Identifies the creation of an AWS Elastic Compute Cloud (EC2) network access control list (ACL) or an entry in a network ACL with a specified rule number.

Rule type: query

Rule indices:

  • filebeat-*
  • logs-aws*

Severity: low

Risk score: 21

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
  • Network Security

Version: 2 (version history)

Added (Elastic Stack release): 7.9.0

Last modified (Elastic Stack release): 7.10.0

Rule authors: Elastic

Rule license: Elastic License

Potential false positives

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Network ACLs may be created by a network administrator. Verify whether the user identity, user agent, and/or hostname should be making changes in your environment. Network ACL creations from unfamiliar users or hosts should be investigated. If a known behavior is causing false positives, it can be excluded from the rule.

Investigation guide

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The AWS Filebeat module must be enabled to use this rule.

Rule query

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event.action:(CreateNetworkAcl or CreateNetworkAclEntry) and
event.dataset:aws.cloudtrail and event.provider:ec2.amazonaws.com and
event.outcome:success

Threat mapping

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Framework: MITRE ATT&CKTM

Rule version history

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Version 2 (7.10.0 release)
  • Formatting only