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    strings.ilike(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  )
34  and sender.email.domain.domain not in ('accountprotection.microsoft.com', 'amex.membershipmail.net')
35
36  and not profile.by_sender().solicited
37
38  // negate highly trusted sender domains unless they fail DMARC authentication
39  and (
40    (
41      sender.email.domain.root_domain in $high_trust_sender_root_domains
42      and not headers.auth_summary.dmarc.pass
43    )
44    or sender.email.domain.root_domain not in $high_trust_sender_root_domains
45  )  
46
47attack_types:
48  - "Credential Phishing"
49tactics_and_techniques:
50  - "Impersonation: Brand"
51  - "Lookalike domain"
52  - "Social engineering"
53detection_methods:
54  - "Header analysis"
55  - "Sender analysis"
56id: "992a9fa9-84ee-5065-8486-b3a2a8ffa676"