Brand impersonation: Wells Fargo

 1name: "Brand impersonation: Wells Fargo"
 2description: |
 3    Impersonation of Wells Fargo Bank.
 4references:
 5  - "https://www.americanbanker.com/news/wells-fargo-customers-targeted-with-phishing-attacks-using-calendar-invites"
 6  - "https://www.wellsfargo.com/biz/help/faqs/credit-card-rewards/"
 7type: "rule"
 8severity: "high"
 9source: |
10  type.inbound
11  and (
12    sender.display_name =~ 'wellsfargo'
13    or strings.ilevenshtein(strings.replace_confusables(sender.display_name), 'wellsfargo') <= 1
14    or regex.icontains(strings.replace_confusables(sender.display_name), 'we(ll|ii)s?\s?farg(o|o͙)')
15    or strings.ilike(sender.email.domain.domain, '*wellsfargo*')
16    or strings.ilike(subject.subject, '*wells fargo security*')
17    or strings.ilike(body.plain.raw, '*wells fargo security team*')
18    or strings.ilike(body.html.inner_text, '*wells fargo security team*')
19  )
20  and sender.email.domain.root_domain not in~ (
21    'wellsfargo.com',
22    'wellsfargoadvisors.com',
23    'transunion.com',
24    'wellsfargoemail.com',
25    'wellsfargorewards.com',
26    'comcast-spectacor.com',
27    'investordelivery.com',
28    'comcastspectacor.com',
29    'wfadvisors.com',
30    'wellsfargomerchantservicesllc.com'
31  )
32  and sender.email.email not in $recipient_emails
33  
34  // negate highly trusted sender domains unless they fail DMARC authentication
35  and (
36    (
37      sender.email.domain.root_domain in $high_trust_sender_root_domains
38      and not headers.auth_summary.dmarc.pass
39    )
40    or sender.email.domain.root_domain not in $high_trust_sender_root_domains
41    or sender.email.email in ("drive-shares-noreply@google.com", "drive-shares-dm-noreply@google.com")  // Google Drive abuse has been observed
42  )  
43
44attack_types:
45  - "Credential Phishing"
46tactics_and_techniques:
47  - "Impersonation: Brand"
48  - "Lookalike domain"
49  - "Social engineering"
50detection_methods:
51  - "Content analysis"
52  - "Sender analysis"
53id: "02d7301f-cc29-5031-9a1e-f013400805ba"