Outbound email contains file-sharing service link sent to external recipient

Cortex XDR Analytics Alert Reference by Alert name

Product
Cortex XDR
Last date published
2026-02-02
Category
Analytics Alert Reference
Index by
Alert name

Synopsis

Activation Period

14 Days

Training Period

30 Days

Test Period

N/A (single event)

Deduplication Period

1 Day

Required Data

  • Requires:
    • Microsoft 365 Emails

Detection Modules

Email

Detector Tags

Exfiltration

ATT&CK Tactic

ATT&CK Technique

Severity

Informational

Description

Identifies outbound emails that include links to file-sharing services sent externally.

Attacker's Goals

Exfiltrate data by sharing a link to a file-sharing service with external recipients, bypassing attachment inspection and potentially evading visibility controls.

Investigative actions

  • Review the shared URL to determine if the file is publicly accessible or shared outside the organization.
  • Check if the file-sharing domain has been previously used by this sender or others in the organization.
  • Investigate recent outbound emails for similar use of file-sharing services or unusual external recipients.

Variations

Outbound email to external recipient(s) uses first-seen for organization file-sharing service

Synopsis

ATT&CK Tactic

ATT&CK Technique

Severity

Informational

Description

Identifies outbound emails that include links to file-sharing services sent externally.

Attacker's Goals

Exfiltrate data by sharing a link to a file-sharing service with external recipients, bypassing attachment inspection and potentially evading visibility controls.

Investigative actions

  • Review the shared URL to determine if the file is publicly accessible or shared outside the organization.
  • Check if the file-sharing domain has been previously used by this sender or others in the organization.
  • Investigate recent outbound emails for similar use of file-sharing services or unusual external recipients.


Outbound email to external recipient(s) uses first-seen for sender file-sharing service

Synopsis

ATT&CK Tactic

ATT&CK Technique

Severity

Informational

Description

Identifies outbound emails that include links to file-sharing services sent externally.

Attacker's Goals

Exfiltrate data by sharing a link to a file-sharing service with external recipients, bypassing attachment inspection and potentially evading visibility controls.

Investigative actions

  • Review the shared URL to determine if the file is publicly accessible or shared outside the organization.
  • Check if the file-sharing domain has been previously used by this sender or others in the organization.
  • Investigate recent outbound emails for similar use of file-sharing services or unusual external recipients.