EMAIL BETA - Unusual hostname for the sending mail server in the email headers

Cortex XDR Analytics Alert Reference by data source

Product
Cortex XDR
Last date published
2025-04-07
Category
Analytics Alert Reference
Index by
data source

Synopsis

Activation Period

14 Days

Training Period

30 Days

Test Period

N/A (single event)

Deduplication Period

3 Days

Required Data

  • Requires:
    • Office 365 Mail

Detection Modules

Email

Detector Tags

ATT&CK Tactic

Defense Evasion (TA0005)

ATT&CK Technique

Impersonation (T1656)

Severity

Low

Description

The detected mail server hostname had not been observed in the organization's emails in the past 30 days.

Attacker's Goals

Impersonating a trusted source, aims to mislead recipients into disclosing private data or performing unsafe acts.

Investigative actions

  • Review the email's received headers, to trace its path and spot spoofing signs.
  • Examine the sender's IP address and domain reputation.
  • Closely inspect the email content for malicious links, attachments, or requests for sensitive information.
  • Monitor further actions taken, such as file downloads or access to potentially malicious links.