sublimemediumRule

Attachment: PDF with suspicious internal object reference identifier

Detects inbound messages containing PDF attachments with a specific internal object reference identifier pattern, which may indicate a crafted or malicious PDF file.

MITRE ATT&CK

T1566.002 T1534 T1656

Detection Query

type.inbound
and any(filter(attachments, .file_type == "pdf"),
        any(file.explode(.),
            .depth == 0
            and any(.scan.strings.strings,
                    strings.contains(., "[<C57237C22450666518136DE404118E5E>")
            )
        )
)

Data Sources

Email MessagesEmail HeadersEmail Attachments

Platforms

Raw Content

name: "Attachment: PDF with suspicious internal object reference identifier"
description: "Detects inbound messages containing PDF attachments with a specific internal object reference identifier pattern, which may indicate a crafted or malicious PDF file."
type: "rule"
severity: "medium"
source: |
  type.inbound
  and any(filter(attachments, .file_type == "pdf"),
          any(file.explode(.),
              .depth == 0
              and any(.scan.strings.strings,
                      strings.contains(., "[<C57237C22450666518136DE404118E5E>")
              )
          )
  )
attack_types:
  - "BEC/Fraud"
tactics_and_techniques:
  - "PDF"
detection_methods:
  - "Content analysis"
  - "File analysis"
id: "f515376e-30f5-56df-86ac-403a0c892466"