Mounting Hidden or WebDav Remote Shares

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Identifies the use of net.exe to mount a WebDav or hidden remote share. This may indicate lateral movement or preparation for data exfiltration.

Rule type: eql

Rule indices:

  • logs-endpoint.events.process-*
  • winlogbeat-*
  • logs-windows.*
  • endgame-*
  • logs-system.security*

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: None

Tags:

  • Domain: Endpoint
  • OS: Windows
  • Use Case: Threat Detection
  • Tactic: Initial Access
  • Tactic: Lateral Movement
  • Data Source: Elastic Endgame
  • Data Source: Elastic Defend

Version: 109

Rule authors:

  • Elastic

Rule license: Elastic License v2

Setup

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Setup

If enabling an EQL rule on a non-elastic-agent index (such as beats) for versions <8.2, events will not define event.ingested and default fallback for EQL rules was not added until version 8.2. Hence for this rule to work effectively, users will need to add a custom ingest pipeline to populate event.ingested to @timestamp. For more details on adding a custom ingest pipeline refer - https://www.elastic.co/guide/en/fleet/current/data-streams-pipeline-tutorial.html

Rule query

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process where host.os.type == "windows" and event.type == "start" and
 ((process.name : "net.exe" or ?process.pe.original_file_name == "net.exe") or ((process.name : "net1.exe" or ?process.pe.original_file_name == "net1.exe") and
 not process.parent.name : "net.exe")) and
 process.args : "use" and
 /* including hidden and webdav based online shares such as onedrive  */
 process.args : ("\\\\*\\*$*", "\\\\*@SSL\\*", "http*") and
 /* excluding shares deletion operation */
 not process.args : "/d*"

Framework: MITRE ATT&CKTM