Brand impersonation: Gusto

 1name: "Brand impersonation: Gusto"
 2description: |
 3    Impersonation of Gusto, a cloud-based payroll management company.
 4type: "rule"
 5severity: "medium"
 6source: |
 7  type.inbound
 8  and (
 9    strings.ilike(sender.display_name, '*gusto*')
10    or strings.ilevenshtein(sender.display_name, 'gusto') <= 1
11    or strings.ilike(sender.email.domain.domain, '*gusto*')
12  )
13  and any(ml.logo_detect(file.message_screenshot()).brands,
14          .name == "Gusto" and .confidence in ("medium", "high")
15  )
16  and sender.email.domain.root_domain !~ 'gusto.com'
17  
18  // negate highly trusted sender domains unless they fail DMARC authentication
19  and (
20    (
21      sender.email.domain.root_domain in $high_trust_sender_root_domains
22      and not headers.auth_summary.dmarc.pass
23    )
24    or sender.email.domain.root_domain not in $high_trust_sender_root_domains
25  )  
26attack_types:
27  - "Credential Phishing"
28tactics_and_techniques:
29  - "Impersonation: Brand"
30  - "Lookalike domain"
31  - "Social engineering"
32detection_methods:
33  - "Computer Vision"
34  - "Content analysis"
35  - "Header analysis"
36  - "Sender analysis"
37id: "54025c1c-34bc-5cbf-97b8-d544806fc587"