sublimelowRule

Link: Invoice or receipt from freemail sender with customer service number

An email from a freemail sender which instructs the recipient to call a fraudulent customer service number.

MITRE ATT&CK

T1566.002 T1534 T1656 T1566.003 T1598 T1598.003 T1566

initial-access

Detection Query

type.inbound
and sender.email.domain.root_domain in $free_email_providers
and any(body.links,
        .display_text == "Unsubscribe"
        and (
          length(.href_url.query_params) == 0 or .href_url.query_params is null
        )
        and (
          .href_url.path == "/"
          or .href_url.path is null
          or (
            .href_url.domain.root_domain == "google.com"
            and not strings.ilike(.href_url.path, "*/forms/*")
          )
        )
)
and sender.email.email not in $sender_emails

Author

vector_sec

Data Sources

Email MessagesEmail HeadersEmail Attachments

Platforms

Raw Content

name: "Link: Invoice or receipt from freemail sender with customer service number"
description: |
  An email from a freemail sender which instructs the recipient to call a fraudulent customer service number.
type: "rule"
severity: "low"
authors:
  - twitter: "vector_sec"
source: |
  type.inbound
  and sender.email.domain.root_domain in $free_email_providers
  and any(body.links,
          .display_text == "Unsubscribe"
          and (
            length(.href_url.query_params) == 0 or .href_url.query_params is null
          )
          and (
            .href_url.path == "/"
            or .href_url.path is null
            or (
              .href_url.domain.root_domain == "google.com"
              and not strings.ilike(.href_url.path, "*/forms/*")
            )
          )
  )
  and sender.email.email not in $sender_emails
attack_types:
  - "BEC/Fraud"
  - "Callback Phishing"
tactics_and_techniques:
  - "Free email provider"
  - "Impersonation: Brand"
  - "Social engineering"
detection_methods:
  - "Content analysis"
  - "Sender analysis"
  - "URL analysis"
id: "3825232d-be75-5ad1-ba7f-a3ec97d23960"