Brand impersonation: Dropbox

 1name: "Brand impersonation: Dropbox"
 2description: |
 3    Impersonation of Dropbox, a file sharing service.
 4type: "rule"
 5severity: "medium"
 6source: |
 7  type.inbound
 8  and (
 9    strings.ilike(sender.display_name, '*dropbox*')
10    or strings.ilevenshtein(sender.display_name, 'dropbox') <= 1
11    or strings.ilike(sender.email.domain.domain, '*dropbox*')
12  )
13  and sender.email.domain.root_domain !~ 'dropbox.com'
14  and any(attachments,
15          .file_type in $file_types_images
16          and any(file.explode(.), strings.ilike(.scan.ocr.raw, "*dropbox*"))
17  )
18  and sender.email.email not in $recipient_emails
19
20  // negate highly trusted sender domains unless they fail DMARC authentication
21  and (
22    (
23      sender.email.domain.root_domain in $high_trust_sender_root_domains
24      and not headers.auth_summary.dmarc.pass
25    )
26    or sender.email.domain.root_domain not in $high_trust_sender_root_domains
27  )  
28
29attack_types:
30  - "Credential Phishing"
31tactics_and_techniques:
32  - "Impersonation: Brand"
33  - "Social engineering"
34detection_methods:
35  - "Content analysis"
36  - "File analysis"
37  - "Header analysis"
38  - "Sender analysis"
39id: "61f11d12-7033-53c9-a95a-df982ff31c4b"