Attempt to Mount SMB Share via Command Line

Elastic Stack Serverless Security

Identifies the execution of macOS built-in commands to mount a Server Message Block (SMB) network share. Adversaries may use valid accounts to interact with a remote network share using SMB.

Rule type: eql

Rule indices:

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

Severity: low

Risk score: 21

Runs every: 5m

Searches indices from: now-9m (https://www.elastic.co/guide/en/elasticsearch/reference/current/common-options.html#date-math[Date Math format], see also Additional look-back time)

Maximum alerts per execution: 100

References:

• https://www.freebsd.org/cgi/man.cgi?mount_smbfs
• https://ss64.com/osx/mount.html

Tags:

• Elastic
• Host
• macOS
• Threat Detection
• Lateral Movement

Version: 101

Rule authors:

• Elastic

Rule license: Elastic License v2

process where event.type in ("start", "process_started") and
  (
    process.name : "mount_smbfs" or
    (process.name : "open" and process.args : "smb://*") or
    (process.name : "mount" and process.args : "smbfs") or
    (process.name : "osascript" and process.command_line : "osascript*mount volume*smb://*")
  ) and
  not process.parent.executable : "/Applications/Google Drive.app/Contents/MacOS/Google Drive"

Framework: MITRE ATT&CKTM

• Tactic:

  • Name: Lateral Movement
  • ID: TA0008
  • Reference URL: https://attack.mitre.org/tactics/TA0008/

• Technique:

  • Name: Remote Services
  • ID: T1021
  • Reference URL: https://attack.mitre.org/techniques/T1021/

• Sub-technique:

  • Name: SMB/Windows Admin Shares
  • ID: T1021.002
  • Reference URL: https://attack.mitre.org/techniques/T1021/002/