Hosts File Modified

edit

The hosts file on endpoints is used to control manual IP address to hostname resolutions. The hosts file is the first point of lookup for DNS hostname resolution so if adversaries can modify the endpoint hosts file, they can route traffic to malicious infrastructure. This rule detects modifications to the hosts file on Microsoft Windows, Linux (Ubuntu or RHEL) and macOS systems.

Rule type: eql

Rule indices:

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

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: 100

References:

Tags:

  • Elastic
  • Host
  • Linux
  • Windows
  • macOS
  • Threat Detection
  • Impact

Version: 5 (version history)

Added (Elastic Stack release): 7.10.0

Last modified (Elastic Stack release): 7.13.0

Rule authors: Elastic

Rule license: Elastic License v2

Investigation guide

edit

Config

For Windows systems using Auditbeat, this rule requires adding C:/Windows/System32/drivers/etc as an additional path in the file_integrity module of auditbeat.yml.

Rule query

edit
file where event.type in ("change", "creation") and file.path :
("/private/etc/hosts", "/etc/hosts",
"?:\\Windows\\System32\\drivers\\etc\\hosts")

Threat mapping

edit

Framework: MITRE ATT&CKTM

Rule version history

edit
Version 5 (7.13.0 release)
  • Updated query, changed from:

    event.category:file and event.type:(change or creation) and
    file.path:("/private/etc/hosts" or "/etc/hosts" or
    "C:\Windows\System32\drivers\etc\hosts")
Version 4 (7.12.0 release)
  • Formatting only
Version 3 (7.11.2 release)
  • Formatting only
Version 2 (7.11.0 release)
  • Formatting only