PowerShell Mailbox Collection Script

Detects PowerShell scripts that can be used to collect data from mailboxes. Adversaries may target user email to collect sensitive information.

Rule type: query

Rule indices:

• winlogbeat-*
• logs-windows.*

Severity: medium

Risk score: 47

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://github.com/dafthack/MailSniper/blob/master/MailSniper.ps1
• https://github.com/center-for-threat-informed-defense/adversary_emulation_library/blob/master/apt29/Archive/CALDERA_DIY/evals/payloads/stepSeventeen_email.ps1

Tags:

• Elastic
• Host
• Windows
• Threat Detection
• Collection
• PowerShell

Version: 1

Rule authors:

• Elastic

Rule license: Elastic License v2

event.category:process and
  (
   powershell.file.script_block_text : (
      "Microsoft.Office.Interop.Outlook" or
      "Interop.Outlook.olDefaultFolders" or
      "::olFolderInBox"
   ) or
   powershell.file.script_block_text : (
      "Microsoft.Exchange.WebServices.Data.Folder" or
      "Microsoft.Exchange.WebServices.Data.FileAttachment"
   )
   )

Framework: MITRE ATT&CKTM

• Tactic:

  • Name: Collection
  • ID: TA0009
  • Reference URL: https://attack.mitre.org/tactics/TA0009/

• Technique:

  • Name: Email Collection
  • ID: T1114
  • Reference URL: https://attack.mitre.org/techniques/T1114/

• Sub-technique:

  • Name: Local Email Collection
  • ID: T1114.001
  • Reference URL: https://attack.mitre.org/techniques/T1114/001/

• Sub-technique:

  • Name: Remote Email Collection
  • ID: T1114.002
  • Reference URL: https://attack.mitre.org/techniques/T1114/002/

• Tactic:

  • Name: Execution
  • ID: TA0002
  • Reference URL: https://attack.mitre.org/tactics/TA0002/

• Technique:

  • Name: Command and Scripting Interpreter
  • ID: T1059
  • Reference URL: https://attack.mitre.org/techniques/T1059/

• Sub-technique:

  • Name: PowerShell
  • ID: T1059.001
  • Reference URL: https://attack.mitre.org/techniques/T1059/001/