sublimemediumRule

Attachment: Dropbox image lure with no Dropbox domains in links

Detects Dropbox phishing emails with no Dropbox links with image attachments from an untrusted sender.

MITRE ATT&CK

T1566 T1566.001 T1566.002 T1598 T1598.003

initial-access

Detection Query

type.inbound
and length(filter(attachments, .file_type not in $file_types_images)) == 0
and any(body.links,
        not strings.ilike(.href_url.domain.root_domain, "dropbox.*")
)
and any(attachments,
        .file_type in $file_types_images
        and any(file.explode(.),
                strings.ilike(.scan.ocr.raw, "*dropbox*")
                and strings.ilike(.scan.ocr.raw, "*review*", "*sign*")
        )
)
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: Dropbox image lure with no Dropbox domains in links"
description: "Detects Dropbox phishing emails with no Dropbox links with image attachments from an untrusted sender."
type: "rule"
severity: "medium"
source: |
  type.inbound
  and length(filter(attachments, .file_type not in $file_types_images)) == 0
  and any(body.links,
          not strings.ilike(.href_url.domain.root_domain, "dropbox.*")
  )
  and any(attachments,
          .file_type in $file_types_images
          and any(file.explode(.),
                  strings.ilike(.scan.ocr.raw, "*dropbox*")
                  and strings.ilike(.scan.ocr.raw, "*review*", "*sign*")
          )
  )
  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:
  - "Credential Phishing"
tactics_and_techniques:
  - "Impersonation: Brand"
  - "Social engineering"
detection_methods:
  - "Content analysis"
  - "File analysis"
  - "Header analysis"
  - "Optical Character Recognition"
  - "Sender analysis"
id: "500eee2d-d793-5450-a87f-825ce27c897d"