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(strings.replace_confusables(sender.display_name),
12                    'american ?express'
13    )
14    or strings.ilike(sender.display_name, "*amer?can expres*")
15    or strings.ilevenshtein(sender.display_name, 'american express') <= 2
16    or strings.icontains(body.current_thread.text,
17                         'american express customer service'
18    )
19    or strings.ilike(sender.email.domain.domain, '*americanexpress*')
20  )
21  and sender.email.domain.root_domain not in (
22    'aexp.com',
23    'americanexpress.ae',
24    'americanexpress.com',
25    'americanexpress.co.uk',
26    'americanexpress.com.bh',
27    'aexpfeedback.com',
28    'amexnetwork.com',
29    'accountonline.com',
30    'transunion.com',
31    'amexgiftcard.com',
32    'amexgbt.com',
33    'herrickstravelamex.com',
34    'citi.com',
35    'secure.com',
36    'nectar.com',
37    'accentinfomedia.com',
38    'egencia.com'
39  )
40  and sender.email.domain.domain not in (
41    'accountprotection.microsoft.com',
42    'amex.membershipmail.net'
43  )
44  and not profile.by_sender().solicited
45  
46  // negate highly trusted sender domains unless they fail DMARC authentication
47  and (
48    (
49      sender.email.domain.root_domain in $high_trust_sender_root_domains
50      and not headers.auth_summary.dmarc.pass
51    )
52    or sender.email.domain.root_domain not in $high_trust_sender_root_domains
53  )  
54attack_types:
55  - "Credential Phishing"
56tactics_and_techniques:
57  - "Impersonation: Brand"
58  - "Lookalike domain"
59  - "Social engineering"
60detection_methods:
61  - "Header analysis"
62  - "Sender analysis"
63id: "992a9fa9-84ee-5065-8486-b3a2a8ffa676"