Attachment: PDF W9 signature reuse

calendar Sep 28, 2026  ยท
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Detects inbound messages containing PDF attachments that match YARA signatures looking for signature re-use.

Sublime rule (View on GitHub)

 1name: "Attachment: PDF W9 signature reuse"
 2description: "Detects inbound messages containing PDF attachments that match YARA signatures looking for signature re-use."
 3type: "rule"
 4severity: "medium"
 5source: |
 6  type.inbound
 7  and any(filter(attachments, .file_type == "pdf"),
 8          any(file.explode(.),
 9              any(.scan.yara.matches, .name == "pdf_w9_signatures")
10          )
11  )  
12attack_types:
13  - "BEC/Fraud"
14tactics_and_techniques:
15  - "PDF"
16  - "Social engineering"
17detection_methods:
18  - "File analysis"
19  - "YARA"
20id: "0f9537df-c71c-5c14-b3f8-0bfd8c5fda2f"
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