Open Redirect: Medium

 1name: "Open Redirect: Medium"
 2description: |
 3    Message contains use of the Medium open redirect. This has been exploited in the wild.
 4type: "rule"
 5severity: "medium"
 6source: |
 7  type.inbound
 8  and any(body.links,
 9      .href_url.domain.root_domain == "medium.com"
10      and strings.icontains(.href_url.path, "/global-identity-2")
11      and strings.icontains(.href_url.query_params, "redirectUrl=")
12      // negate redirects to medium.com
13      and not regex.icontains(.href_url.query_params,
14                              'redirectUrl=(?:(?:https?(?:%3a|:))?(?:%2f|\/){2})?(?:[a-z0-9]+\.)*medium\.com'
15      )
16  )
17  and (
18    not profile.by_sender().solicited
19    or (
20      profile.by_sender().any_messages_malicious_or_spam
21      and not profile.by_sender().any_false_positives
22    )
23  )
24  
25  // negate highly trusted sender domains unless they fail DMARC authentication
26  and (
27    (
28      sender.email.domain.root_domain in $high_trust_sender_root_domains
29      and not headers.auth_summary.dmarc.pass
30    )
31    or sender.email.domain.root_domain not in $high_trust_sender_root_domains
32  )  
33attack_types:
34  - "Credential Phishing"
35  - "Malware/Ransomware"
36tactics_and_techniques:
37  - "Open redirect"
38detection_methods:
39  - "Sender analysis"
40  - "URL analysis"
41id: "18c6aa1b-dee4-5ca6-a3bd-706cc7368e28"