Brand Impersonation: Stripe

 1name: "Brand Impersonation: Stripe"
 2description: |
 3    Impersonation of Stripe, usually for credential theft.
 4type: "rule"
 5severity: "high"
 6source: |
 7  type.inbound
 8  and (
 9    // Display name after replacing unicode confusables is stripe
10    (
11      sender.display_name =~ 'stripe'
12      or (
13          strings.istarts_with(sender.display_name, 'stripe ')
14          and not sender.display_name in~ ('Stripe & Stare')
15      )
16      or strings.replace_confusables(sender.display_name) =~ 'stripe'
17    )
18    or (
19      // the edit distance is 1 or 2
20      strings.ilevenshtein(strings.replace_confusables(sender.display_name),
21                           'stripe'
22      ) <= 2
23      // the length is the same as "stripe"
24      and length(sender.display_name) == 6
25      // and not one of these english words that matches the edit distance
26      and not sender.display_name in~ (
27        "strive",
28        "stride",
29        "strife",
30        "strike",
31        "strobe",
32        "streps",
33        "string",
34        "scribe",
35        "straye", // a shoe company?
36        "storie", // storiesbystorie.com
37        "stryve", // a food/snack company stryve.com
38        "shrine", // common word
39        "s.ride" // cab/taxi company
40      )
41    )
42  )
43  and sender.email.domain.root_domain not in~ ('stripe.com')
44  and sender.email.email not in $recipient_emails
45  
46  // Stripe adds a custom header
47  // don't match messages with the header
48  and not any(headers.hops, any(.fields, .name == "X-Stripe-EID"))
49  
50  // negate highly trusted sender domains unless they fail DMARC authentication
51  and (
52    (
53      sender.email.domain.root_domain in $high_trust_sender_root_domains
54      and not headers.auth_summary.dmarc.pass
55    )
56    or sender.email.domain.root_domain not in $high_trust_sender_root_domains
57  )  
58attack_types:
59  - "Credential Phishing"
60tactics_and_techniques:
61  - "Impersonation: Brand"
62  - "Lookalike domain"
63  - "Social engineering"
64detection_methods:
65  - "Header analysis"
66  - "Sender analysis"
67id: "862d4654-4a32-50c1-a441-b3a5106be174"