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.com',
19    'americanexpress.co.uk',
20    'aexpfeedback.com',
21    'amexnetwork.com',
22    'accountonline.com',
23    'transunion.com',
24    'amexgiftcard.com',
25    'amexgbt.com',
26    'herrickstravelamex.com',
27    'citi.com',
28    'secure.com'
29  )
30  and sender.email.domain.domain not in ('accountprotection.microsoft.com', 'amex.membershipmail.net')
31
32  and not profile.by_sender().solicited
33
34  // negate highly trusted sender domains unless they fail DMARC authentication
35  and
36  (
37    (
38      sender.email.domain.root_domain in $high_trust_sender_root_domains
39      and (
40        any(distinct(headers.hops, .authentication_results.dmarc is not null),
41            strings.ilike(.authentication_results.dmarc, "*fail")
42        )
43      )
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"