EMAIL BETA - Email attachment with a potentially malicious file extension

Cortex XSIAM Analytics Alert Reference by Alert name

Product
Cortex XSIAM
Last date published
2025-04-07
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:
    • Office 365 Mail

Detection Modules

Email

Detector Tags

ATT&CK Tactic

ATT&CK Technique

Severity

Informational

Description

The email message includes attachments with file types that are typically blocked by the email vendor as a precaution due to their suspicious nature.

Attacker's Goals

  • Deploy malicious attachments through emails to compromise systems, gain unauthorized access, or facilitate cyber threats.

Investigative actions

  • Check the file types and investigate the legitimacy of files intended to be sent via email.
  • Scrutinize the attachments for any suspicious indications.
  • Confirm whether the attachments were successfully delivered to the recipient's mailbox.
  • If the attachments were delivered successfully, verify whether the recipient downloaded them.
  • Check the email address for any unusual spellings.
  • Check the email address for any missing letters.
  • Verify the sender's domain to confirm its legitimacy.
  • Examine the sender's IP address and reputation.
  • Verify whether the sender's IP address has appeared in different log sources before.
  • Verify if the sender's IP address is identifiable.

Variations

EMAIL BETA - Attachment(s) with a potentially malicious file extension unusual for the organization

Synopsis

ATT&CK Tactic

ATT&CK Technique

Severity

Medium

Description

At least one attachment with a potentially malicious file extension was received in an email for the first time within the organization in the past 30 days.

Attacker's Goals

  • Deploy malicious attachments through emails to compromise systems, gain unauthorized access, or facilitate cyber threats.

Investigative actions

  • Check the file types and investigate the legitimacy of files intended to be sent via email.
  • Scrutinize the attachments for any suspicious indications.
  • Confirm whether the attachments were successfully delivered to the recipient's mailbox.
  • If the attachments were delivered successfully, verify whether the recipient downloaded them.
  • Check the email address for any unusual spellings.
  • Check the email address for any missing letters.
  • Verify the sender's domain to confirm its legitimacy.
  • Examine the sender's IP address and reputation.
  • Verify whether the sender's IP address has appeared in different log sources before.
  • Verify if the sender's IP address is identifiable.


EMAIL BETA - Attachment(s) with a potentially malicious file extension unusual for the recipient

Synopsis

ATT&CK Tactic

ATT&CK Technique

Severity

Low

Description

At least one attachment with a potentially malicious file extension was received in an email for the first time for the recipient in the past 30 days.

Attacker's Goals

  • Deploy malicious attachments through emails to compromise systems, gain unauthorized access, or facilitate cyber threats.

Investigative actions

  • Check the file types and investigate the legitimacy of files intended to be sent via email.
  • Scrutinize the attachments for any suspicious indications.
  • Confirm whether the attachments were successfully delivered to the recipient's mailbox.
  • If the attachments were delivered successfully, verify whether the recipient downloaded them.
  • Check the email address for any unusual spellings.
  • Check the email address for any missing letters.
  • Verify the sender's domain to confirm its legitimacy.
  • Examine the sender's IP address and reputation.
  • Verify whether the sender's IP address has appeared in different log sources before.
  • Verify if the sender's IP address is identifiable.