sublimelowRule

Fake shipping notification with link to free file hosting

This rule detects spam emails impersonating FedEx, UPS, or USPS with links to free file hosting.

MITRE ATT&CK

initial-access

Detection Query

type.inbound
and length(attachments) == 0
and (
  regex.icontains(coalesce(body.html.inner_text, body.html.display_text),
                  '\bf[ _]?e[ _]?d[ _]?e[ _]?x\b'
  )
  and sender.email.domain.domain != "fedex.com"
  and headers.return_path.domain.domain != sender.email.domain.domain
  and any(body.links, strings.contains(.display_text, "track"))
  and length(body.links) < 10
)
and any(body.links,
        .href_url.domain.domain in $free_file_hosts
        or .href_url.domain.root_domain in $free_file_hosts
)
and (
  (
    sender.email.domain.root_domain in $free_email_providers
    and sender.email.email not in $sender_emails
  )
  or (
    sender.email.domain.root_domain not in $free_email_providers
    and sender.email.domain.root_domain not in $sender_domains
  )
  or sender.email.domain.valid == false
)

Data Sources

Email MessagesEmail HeadersEmail Attachments

Platforms

References

https://playground.sublimesecurity.com?id=64feb22a-03e8-4d8f-83f6-a828dc5e3540

Raw Content

name: "Fake shipping notification with link to free file hosting"
description: |
  This rule detects spam emails impersonating FedEx, UPS, or USPS with links to free file hosting.
references:
  - "https://playground.sublimesecurity.com?id=64feb22a-03e8-4d8f-83f6-a828dc5e3540"
severity: "low"
type: "rule"
source: |
  type.inbound
  and length(attachments) == 0
  and (
    regex.icontains(coalesce(body.html.inner_text, body.html.display_text),
                    '\bf[ _]?e[ _]?d[ _]?e[ _]?x\b'
    )
    and sender.email.domain.domain != "fedex.com"
    and headers.return_path.domain.domain != sender.email.domain.domain
    and any(body.links, strings.contains(.display_text, "track"))
    and length(body.links) < 10
  )
  and any(body.links,
          .href_url.domain.domain in $free_file_hosts
          or .href_url.domain.root_domain in $free_file_hosts
  )
  and (
    (
      sender.email.domain.root_domain in $free_email_providers
      and sender.email.email not in $sender_emails
    )
    or (
      sender.email.domain.root_domain not in $free_email_providers
      and sender.email.domain.root_domain not in $sender_domains
    )
    or sender.email.domain.valid == false
  )

attack_types:
  - "Spam"
tactics_and_techniques:
  - "Free file host"
  - "Impersonation: Brand"
  - "Social engineering"
detection_methods:
  - "Content analysis"
  - "Header analysis"
  - "Sender analysis"
id: "6d3fe05e-8ee6-586e-a2c6-60488ecf347a"