sublimemediumRule

Attachment: PDF with dub.sh shortened link

Catches messages carrying PDF attachments that embed links shortened through the dub.sh service. The lures vary widely, from fake 'password protected document' or e-signature notifications to business submission and proposal requests, but each relies on a PDF containing a shortened link to obscure the true destination and evade URL-based filtering.

MITRE ATT&CK

T1566 T1566.001 T1566.002 T1598 T1534 T1656 T1036 T1027

initial-accessdefense-evasion

Detection Query

type.inbound
and any(attachments,
        .file_type == "pdf"
        and any(file.explode(.),
                any(.scan.url.urls, .domain.root_domain == "dub.sh")
        )
)

Data Sources

Email MessagesEmail HeadersEmail Attachments

Platforms

Raw Content

name: "Attachment: PDF with dub.sh shortened link"
description: "Catches messages carrying PDF attachments that embed links shortened through the dub.sh service. The lures vary widely, from fake 'password protected document' or e-signature notifications to business submission and proposal requests, but each relies on a PDF containing a shortened link to obscure the true destination and evade URL-based filtering."
type: "rule"
severity: "medium"
source: |
  type.inbound
  and any(attachments,
          .file_type == "pdf"
          and any(file.explode(.),
                  any(.scan.url.urls, .domain.root_domain == "dub.sh")
          )
  )
attack_types:
  - "Credential Phishing"
  - "BEC/Fraud"
tactics_and_techniques:
  - "PDF"
  - "Social engineering"
  - "Evasion"
detection_methods:
  - "File analysis"
  - "URL analysis"
id: "36c01114-5437-5417-83ca-e8bdcd0c4488"