Link: Flagged bit.ly link

 1name: "Link: Flagged bit.ly link"
 2description: |
 3    Shortened link is blocked or gated by bit.ly. Indicator of malicious email.
 4type: "rule"
 5severity: "medium"
 6source: |
 7  type.inbound
 8  and any(body.links,
 9          // contains bit.ly link
10          .href_url.domain.root_domain == "bit.ly"
11          // link doesn't forward through
12          and ml.link_analysis(.).effective_url.domain.domain == "bit.ly"
13          // blocked or gated by bit.ly
14          and strings.ilike(ml.link_analysis(.).final_dom.display_text,
15                            "*link*blocked*",
16                            "*flagged*by*"
17          )
18  )
19
20  // negate highly trusted sender domains unless they fail DMARC authentication
21  and (
22    (
23      sender.email.domain.root_domain in $high_trust_sender_root_domains
24      and not headers.auth_summary.dmarc.pass
25    )
26    or sender.email.domain.root_domain not in $high_trust_sender_root_domains
27  )
28  and (
29    not profile.by_sender().solicited
30    or (
31      profile.by_sender().any_messages_malicious_or_spam
32      and not profile.by_sender().any_false_positives
33    )
34  )
35  and not profile.by_sender().any_false_positives  
36tags:
37  - "Attack surface reduction"
38attack_types:
39  - "Credential Phishing"
40tactics_and_techniques:
41  - "Evasion"
42detection_methods:
43  - "URL analysis"
44id: "1528eb6c-22fa-5879-b48c-53ee466fde23"