sublimemediumRule

Attachment: PDF W9 signature reuse

Detects inbound messages containing PDF attachments that match YARA signatures looking for signature re-use.

MITRE ATT&CK

initial-access

Detection Query

type.inbound
and any(filter(attachments, .file_type == "pdf"),
        any(file.explode(.),
            any(.scan.yara.matches, .name == "pdf_w9_signatures")
        )
)

Data Sources

Email MessagesEmail HeadersEmail Attachments

Platforms

Raw Content

name: "Attachment: PDF W9 signature reuse"
description: "Detects inbound messages containing PDF attachments that match YARA signatures looking for signature re-use."
type: "rule"
severity: "medium"
source: |
  type.inbound
  and any(filter(attachments, .file_type == "pdf"),
          any(file.explode(.),
              any(.scan.yara.matches, .name == "pdf_w9_signatures")
          )
  )
attack_types:
  - "BEC/Fraud"
tactics_and_techniques:
  - "PDF"
  - "Social engineering"
detection_methods:
  - "File analysis"
  - "YARA"
id: "0f9537df-c71c-5c14-b3f8-0bfd8c5fda2f"