Brand impersonation: American Express (AMEX)

 1name: "Brand impersonation: American Express (AMEX)"
 2description: |
 3    Impersonation of the credit card provider American Express.
 4references:
 5  - "https://www.inc.com/joseph-steinberg/american-express-users-beware-this-scam.html"
 6type: "rule"
 7severity: "low"
 8source: |
 9  type.inbound
10  and (
11    regex.icontains(sender.display_name, 'american ?express')
12    or strings.ilike(sender.display_name, "*amer?can expres*")
13    or strings.ilevenshtein(sender.display_name, 'american express') <= 2
14    or strings.ilike(sender.email.domain.domain, '*americanexpress*')
15  )
16  and sender.email.domain.root_domain not in (
17    'aexp.com',
18    'americanexpress.ae',
19    'americanexpress.com',
20    'americanexpress.co.uk',
21    'americanexpress.com.bh',
22    'aexpfeedback.com',
23    'amexnetwork.com',
24    'accountonline.com',
25    'transunion.com',
26    'amexgiftcard.com',
27    'amexgbt.com',
28    'herrickstravelamex.com',
29    'citi.com',
30    'secure.com',
31    'nectar.com',
32    'accentinfomedia.com',
33    'egencia.com'
34  )
35  and sender.email.domain.domain not in ('accountprotection.microsoft.com', 'amex.membershipmail.net')
36
37  and not profile.by_sender().solicited
38
39  // negate highly trusted sender domains unless they fail DMARC authentication
40  and (
41    (
42      sender.email.domain.root_domain in $high_trust_sender_root_domains
43      and not headers.auth_summary.dmarc.pass
44    )
45    or sender.email.domain.root_domain not in $high_trust_sender_root_domains
46  )  
47
48attack_types:
49  - "Credential Phishing"
50tactics_and_techniques:
51  - "Impersonation: Brand"
52  - "Lookalike domain"
53  - "Social engineering"
54detection_methods:
55  - "Header analysis"
56  - "Sender analysis"
57id: "992a9fa9-84ee-5065-8486-b3a2a8ffa676"