sublimehighRule

Attachment with suspicious author (unsolicited)

Recursively scans files and archives to detect embedded docx files with a specific author.

MITRE ATT&CK

Detection Query

type.inbound
and any(attachments,
        (
          .file_extension in~ ("doc", "docm", "docx", "dot", "dotm")
          or .file_extension in~ $file_extensions_common_archives
        )
        and any(file.explode(.), strings.ilike(.scan.docx.author, "root"))
)
and (
  not profile.by_sender().solicited
  or (
    profile.by_sender().any_messages_malicious_or_spam
    and not profile.by_sender().any_messages_benign
  )
)

Data Sources

Email MessagesEmail HeadersEmail Attachments

Platforms

Raw Content

name: "Attachment with suspicious author (unsolicited)"
description: |
  Recursively scans files and archives to detect embedded docx files with a specific author.
type: "rule"
severity: "high"
source: |
  type.inbound
  and any(attachments,
          (
            .file_extension in~ ("doc", "docm", "docx", "dot", "dotm")
            or .file_extension in~ $file_extensions_common_archives
          )
          and any(file.explode(.), strings.ilike(.scan.docx.author, "root"))
  )
  and (
    not profile.by_sender().solicited
    or (
      profile.by_sender().any_messages_malicious_or_spam
      and not profile.by_sender().any_messages_benign
    )
  )
attack_types:
  - "Malware/Ransomware"
detection_methods:
  - "File analysis"
  - "Sender analysis"
id: "40f518b9-88a2-59c5-8f6a-54bfd0fdf209"