Well-known brand in sender headers with header inconsistencies

Cortex XDR Analytics Alert Reference by Alert name

Product
Cortex XDR
Last date published
2026-03-10
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

Brand Impersonation

ATT&CK Tactic

Defense Evasion (TA0005)

ATT&CK Technique

Impersonation (T1656)

Severity

Informational

Description

Sender headers include a well-known brand with header inconsistencies indicating possible impersonation.

Attacker's Goals

Impersonate known legitimate brands or other technological entities to trick recipients into disclosing information or executing malicious code unwillingly.

Investigative actions

  • Identify the specific emails responsible for the accumulation of these alerts.
  • Review their headers and content for patterns or anomalies.
  • Assess the email's context and attack techniques to determine the potential risk.
  • Review the email headers and metadata of each flagged email to identify potential spoofing techniques or unusual routing patterns.
  • Analyze any URLs or attachments in a secure sandbox environment to detect possible malware or phishing attempts.
  • Engage potentially affected users to understand if any actions were taken in response to these emails, which could increase the overall risk.
  • Document and escalate findings in case this is a broader phenomenon.