sublimelowRule

Russia return-path TLD (untrusted sender)

The return-path header is a .ru TLD from an untrusted sender.

MITRE ATT&CK

T1566.002 T1534 T1656 T1566 T1566.001 T1598 T1204.002 T1486

Detection Query

type.inbound
and headers.return_path.domain.tld == "ru"
and sender.email.domain.domain != "corp.mail.ru"
and sender.email.domain.domain != "calendar.yandex.ru"
and (
  (
    profile.by_sender().prevalence in ("new", "outlier")
    and not profile.by_sender().solicited
  )
  or (
    profile.by_sender().any_messages_malicious_or_spam
    and not profile.by_sender().any_messages_benign
  )
)
and not profile.by_sender().any_messages_benign

Data Sources

Email MessagesEmail HeadersEmail Attachments

Platforms

Tags

Attack surface reduction

Raw Content

name: "Russia return-path TLD (untrusted sender)"
description: |
  The return-path header is a .ru TLD from an untrusted sender.
type: "rule"
severity: "low"
source: |
  type.inbound
  and headers.return_path.domain.tld == "ru"
  and sender.email.domain.domain != "corp.mail.ru"
  and sender.email.domain.domain != "calendar.yandex.ru"
  and (
    (
      profile.by_sender().prevalence in ("new", "outlier")
      and not profile.by_sender().solicited
    )
    or (
      profile.by_sender().any_messages_malicious_or_spam
      and not profile.by_sender().any_messages_benign
    )
  )
  and not profile.by_sender().any_messages_benign
tags:
  - "Attack surface reduction"
attack_types:
  - "BEC/Fraud"
  - "Credential Phishing"
  - "Malware/Ransomware"
detection_methods:
  - "Header analysis"
  - "Sender analysis"
id: "588b3954-c03a-57fb-b5a4-abf993a8c003"